Thank you so much! I need to check the wires on mine and information like this is priceless. Saves me tons of time. I hate interior work especially because of all the clips, tiny screws, panels and everything else. Not to mention the awkward angles you have to orient yourself in to get underneath there. Cheers bud!
This was a great demonstration. But what was the truck doing to need this unit replaced? I am having an assortment of clicking sounds after R&R the transmission for an overhaul. Nope, I did not pinch any wires. And yes, everything is connected correctly. The truck came in with the 2WD light on. Now, the lights flash but stays in 4WD high. And after a few minutes of clicking, Mr. Fuse does his thing. I should clarify, the clicking is under the dash, and the transfer case motor is bumping erratically.
Let me tell you this video saved me a lot of money by showing me how to do this myself. I would like to add that I had a 20 amp fuse under the hood labeled ATC that kept blowing too. After I replaced my TCCM it initially didn't resolve the problem but when I remember to check that fuse again sure enough it was blown again. Once I replaced it everything worked. Fingers crossed 🤞 it stays that way! Thanks for making this video!
Thank you so much. Super helpful video. Seemed simple enough so I went for it. Had to come back and watch again to see just how you twisted the TCCM to get it out as mine was fighting me.
@Susan Kassebaum Lol, I tried to film it the best I could at the time. Once you lift that plastic tab, you can slide it out a bit and turn it. Some of them will come straight out without turning it.
Just bought a 99 blazer. No lights are lit on the 4wd selector switch. Switch does not change the 4wd mode, it stays in 2wd. Switch ohms out good and no blown fuses. What do you think I should look at next?
I have the same truck. And my truck won’t shift pass 2nd gear had the transmission rebuilt still doesn’t shift. Will this cause it not to shift pass 2nd gear? Or is it something else
It can be. If it's in Drive and is still kicking or just stays in first or even drops all together. Tells me something was over looked when it was rebuilt. Could be an issue with internal solenoid. Doesn't hurt to swap out a module to see first. They are easy to find at most junk yards. 😎👍🍻
I have a 2000 Chevy Silverado LS 1500 and I don't have room to pull that module out! No room to move it to the left without hitting the side of the box it sits in and the metal housing the instrument panel sits in is in the way on the right. No matter how I move the module, there is limited space and no way to just pull it out! Getting it out will involve taking the entire dash apart which my Chilton say is a big job even for and experienced mechanic! Just my luck.
Sorry only seeing your post now. I hope you didn't pull your dash!. It will slide out once you get the wire harnesses are out the way. Sometimes you'll have to turn the Module around a bit. Let me know if you got it.
@@terryhollingsworth I just did a 2000 Chevy and it will come out of there, pull the left side out a bit and turn it while youre pulling. You might need bandaids on your knuckles when you get done, but it will go.
I’ve checked my switched grounds and tried replacing Tccm with a used one my issue is all the lights come on and it intermittently will switch between 4wd hi / low and back into 2wd I unplugged the tccm let it sit for a few days waiting on used one to arrive and tried new one lights wouldn’t even come on swapped the old one back in and everything worked fine come outside to check it next morning acting us once again doing same issue as before
This was the problem on my 2002 2500HD. If you disconnected the ground, you could hear the relays click and the 4wd would work until you shut it off, then service 4wd came back on. Finding one of the TCCMs with the green plug (NP2) was difficult and expensive.
'99 Sierra 1500 here. My Service 4WD light now comes on after I drive the vehicle for 20 to 30 minutes. Last year, it was after 1 to 2 hours. All of the 4x4 modes work correctly. I wonder if this could be my issue. Thanks for the video... It doesn't look too hard to get to.
Not yet. I haven't done much looking into it since I posted, since I have been recovering from surgery. 4Wd does still work as normal, though.@@DocAnkh
@@chrisinestes That sounds more like a short at 1 of the connectors or the ground. The ground is on the driver's side, under the vehicle near the driver seat. I can't remember if it's bolted to the frame or body.
I have a 99 silverado the 4x4 switch has no lights, i have replaced the switch itself, checked fuses and cleaned the groud cables and the new switch still dont light up. Could the tccm be the problem?
@Nickerson No, it's most likely the Shift Motor on the transfer case. It's a common problem with GMs. You can pull the motor. It can also be done without moving the forward drive shaft. Once off you can turn the spine with a pair pliers to ingage or disengage 4x4 wheel drive. Usually it will display 4x4 service needed or something to that point on the dash. Sometimes the 4x4 button or 2wd will blink.😎👍🍻
I'm having some issues trying to find my tccm i have a 99 suburban 2500 I'm pretty sure it's up underneath by the steering column truck keeps wanting to go in and out of four-wheel drive and none of the lights come on bought a new switch and and everything four-wheel drive service switch comes on 😊
That wouldn't be a TCCM problem. That sounds more like a 'Control Motor' issue. It's located on the transfer case left side (driver's side). It can be removed without moving the forward drive shaft. To check, pull the control motor (while in 2wd engine off) and turn the shaft in the transfer case, start the truck in neutral. After starting, See if it goes in 4wd. If your display is say 4wd needs service, it's the problem. It's quite common on GMs.
Do you think if i replace mine on my 98 bravads it will fix the issue i have i jack it up and the tires are spinning at 15mph the front tire starts sinning then i hear 4 clicks coming from the interior and my service 4wd light comes on
Doses it ingage and disengage? (In 4x4). On GMs it's typically the "Shift Motor" on the transfer case. The TCCM Rarely goes out. Typically it's the Motor. The Module rarely goes out. You could have a short at one of the pens going into the Module or at the ground source. I Can't remember if the ground source is on the body or the frame. It's Up near the driver's side seat seat on the body or frame. I Would pull the shift motor off the transfer case and manually. Turn the spine and see if it goes in or out of four wheel. If it does then you have your answer.
@@DocAnkh it engages for a second and you can tell cause the wheel starts spinning with a good ammount of speed and power then i get a service awd light and it instantly stops shift motor turns free same with the spine on the transfer case , im gonna check the ground and try it again
Thank you for taking the time. I've had half a dozen people tell me I'm nutz because I don't find it behind the pass kick. (99 Tahoe 4dr) I have an intermittent module that lights all 4wd switch lights and the 4wd service light as well as fails to show on the CAN buss when it's out, hoping it's a connection. fwiw I'm subbed
Hi Scott, hope you got it resolved. Usually if all the lights light up and 4wd service light is on, its the external shift motor on the transfer case. Its not engaging. Its a common problem. Yes, they sometimes are behind the right kick panel. I had 2 out in the pasture that had the module located there. I have since sent them on to the junk yard. I have had people say to me you don't know what you're looking at. 1 of those people got to see with his own eyes. Lets just say it was priceless.🤣😎👍🍻
Also. This module going bad caused my transmission to shift erratically- it would short shift gears and lock the converter up. I’d be in overdrive at 15 MPH, bogging down the motor hard. It was an intermittent issue, unplugging the orange plug here made the transmission shift perfect, but obviously I lost 4WD doing that. Bought a new box off eBay and installed it- ended up removing a DORMAN box out of the vehicle, which means at 250k miles that this is at least the second time it’s been replaced.
Hi Timmy, Hope you got it resolved. If your still having issues with it, it could be a number of different things. Reply back to me and I'll see if I can help you further.
My 'service 4wd' light came on. Like a dummy I put it in 4hi. Now the truck will go into 4l, auto 4wd, and of course 4hi, but WILL NOT go into 2wd. I tried checking fuses, unhooked battery, etc with no luck. Any info is appreciated
You sometimes can go back and forth from neutral and park while hitting 2wd. That sometimes will at least get you back in 2wd. The problem is in your 4x4 shift motor. Its a very common problem. Its located on transfer case next to the forward drive shaft (driver's side). You can remove it without removing the drive shaft. If hitting the button does'nt work, you have to remove the shift motor and manually turn it back to 2wd. The "Service 4wd Soon " light will not go out till replace shift motor. Driving awhile without the shift motor in it will not hurt anything if you need time to buy the new part. 😎👍🍻
Mine makes the clicking sound your referring to. Then after 2 attempts at trying to switch modes, it sets the 4hi light and message center says service 4wd. Is that what yours was doing as well? Why was the fix?
@@mark98070 mine was clicking like it had a glitch in the module . And I was unable to change the modes from 2 high to 4 low or 4 high. I replaced the module and then it got rid of the problem. I am now able to switch modes
Sounds that you need a shift control motor. Its located on the transfer case upper driver's side. There are plenty of videos that show the removal and install, it also can be done without removing the forward drive shaft. Its a very common problem with GMs. 😎👍🍻
Thanks man I have no signal on my brown wire that should be key on hot to the front actuator. Their is a splice around the module so this video is exactly what I searched for. What was the symptoms for your module replacement? My transfer case switched and front drive shaft starts spinning but front actuator which is new doesnt engage 4hi just flashes. No service 4wd light or codes
@@brianmellard5886 Dude the snow went away so I stopped trouble shooting lol. Happens every spring! I get into it than give up when the snows gone. But I’m getting ready to replace transfer case it’s clicking and crunching so I’m going to try checking the signal into the tccm and out of it. If it doesn’t work myself and my coworker came up with the idea we will just run a hot wire right to the front axle actuator. So I’m theory when I press the 4wd high button it should work
@@brianmellard5886 I’ll let you know what I find at the module when I access it. But since everything else is working adding a toggle switch just to send power to actuator rather than the TCCM doing it should work.
For me it was because I had service 4wd warning light on at all times and the lights on the 4wd switch didn't work and you couldn't switch to any of the drive modes. I replaced the switch first because I have seen some say that is the problem. The switch is inexpensive I think I paid $15 for a knock off on eBay but that wasn't my problem. So I replaced the TCCM and it resolved my issues. I also had a 20a fuse under the hood labeled ATC that kept blowing. Replacing my TCCM has resolved that issue as well.
@@stopthenonsense971 thanks for getting back yo me! I am wondering if the module in the dash is bad! I am going to swap it out with my sons truck before I go further! It clicks a lot, and the truck needs to warm up in order for the switch to work, the trouble light to go off, as well as able to change from one to the next. I will let everyone know once i am finally got it fixed!
@@stopthenonsense971 hello I just have the same issue that you have with my Silverado 2000, but I changed the switch already but I keep getting all the lights on, and it does not do anything, my question is if you had to program the TCCM, with a computer or you just replace it with a used one or a new one. Thank you in advance.
If it's not disengaging or not going into 4x4 drive it's the shift motor on the Transfer case. You go under and turn the spine with a pair of pliers. It's OK to pull it and run the vehicle until your ready to replace the shift motor. It's a common problem with GMs. Sorry for only getting back to you now. TH-cam didn't notify of your comment.😎👍🍻
Thank you so much! I need to check the wires on mine and information like this is priceless. Saves me tons of time. I hate interior work especially because of all the clips, tiny screws, panels and everything else. Not to mention the awkward angles you have to orient yourself in to get underneath there. Cheers bud!
This was a great demonstration. But what was the truck doing to need this unit replaced?
I am having an assortment of clicking sounds after R&R the transmission for an overhaul. Nope, I did not pinch any wires. And yes, everything is connected correctly. The truck came in with the 2WD light on. Now, the lights flash but stays in 4WD high. And after a few minutes of clicking, Mr. Fuse does his thing.
I should clarify, the clicking is under the dash, and the transfer case motor is bumping erratically.
Let me tell you this video saved me a lot of money by showing me how to do this myself. I would like to add that I had a 20 amp fuse under the hood labeled ATC that kept blowing too. After I replaced my TCCM it initially didn't resolve the problem but when I remember to check that fuse again sure enough it was blown again. Once I replaced it everything worked. Fingers crossed 🤞 it stays that way! Thanks for making this video!
Thank you so much. Super helpful video. Seemed simple enough so I went for it. Had to come back and watch again to see just how you twisted the TCCM to get it out as mine was fighting me.
Me too. I was starting to think my dash support was different until I watched the video again and saw how he spun the TCCM to get it out.
@Susan Kassebaum Lol, I tried to film it the best I could at the time. Once you lift that plastic tab, you can slide it out a bit and turn it. Some of them will come straight out without turning it.
Great video thanks for taking the time.
Thank you so much for taking the time to make this!
Just bought a 99 blazer.
No lights are lit on the 4wd selector switch.
Switch does not change the 4wd mode, it stays in 2wd.
Switch ohms out good and no blown fuses.
What do you think I should look at next?
Just what I was looking for. Thank you so much!
Thank you I've been trying to figure out how to get to that, and that solved my problem
Your welcome. Remove the 2 bolts on the housing, theres usually enough play to get to the bottom.
I have the same truck. And my truck won’t shift pass 2nd gear had the transmission rebuilt still doesn’t shift. Will this cause it not to shift pass 2nd gear? Or is it something else
It can be. If it's in Drive and is still kicking or just stays in first or even drops all together. Tells me something was over looked when it was rebuilt. Could be an issue with internal solenoid. Doesn't hurt to swap out a module to see first. They are easy to find at most junk yards. 😎👍🍻
I have a 2000 Chevy Silverado LS 1500 and I don't have room to pull that module out! No room to move it to the left without hitting the side of the box it sits in and the metal housing the instrument panel sits in is in the way on the right. No matter how I move the module, there is limited space and no way to just pull it out! Getting it out will involve taking the entire dash apart which my Chilton say is a big job even for and experienced mechanic! Just my luck.
Sorry only seeing your post now. I hope you didn't pull your dash!. It will slide out once you get the wire harnesses are out the way. Sometimes you'll have to turn the Module around a bit. Let me know if you got it.
I tried and tried. There is just not way to do it. Thanks for the reply anyway.
@@terryhollingsworth I just did a 2000 Chevy and it will come out of there, pull the left side out a bit and turn it while youre pulling. You might need bandaids on your knuckles when you get done, but it will go.
Thanks, for the video. Really helpful
I’ve checked my switched grounds and tried replacing Tccm with a used one my issue is all the lights come on and it intermittently will switch between 4wd hi / low and back into 2wd I unplugged the tccm let it sit for a few days waiting on used one to arrive and tried new one lights wouldn’t even come on swapped the old one back in and everything worked fine come outside to check it next morning acting us once again doing same issue as before
This was the problem on my 2002 2500HD. If you disconnected the ground, you could hear the relays click and the 4wd would work until you shut it off, then service 4wd came back on. Finding one of the TCCMs with the green plug (NP2) was difficult and expensive.
Yes, those are hard to find. Did you end up buying it on Ebay?😎👍🍻
'99 Sierra 1500 here. My Service 4WD light now comes on after I drive the vehicle for 20 to 30 minutes. Last year, it was after 1 to 2 hours. All of the 4x4 modes work correctly. I wonder if this could be my issue. Thanks for the video... It doesn't look too hard to get to.
Did you get it resolved?
Not yet. I haven't done much looking into it since I posted, since I have been recovering from surgery. 4Wd does still work as normal, though.@@DocAnkh
@@chrisinestes That sounds more like a short at 1 of the connectors or the ground. The ground is on the driver's side, under the vehicle near the driver seat. I can't remember if it's bolted to the frame or body.
Next time I have it on the lift, I'll check that out. My mechanic friend says it's often an anti-lock brake sensor. @@DocAnkh
Great video. I fought mine a little getting it out- didn’t help that it’s below zero degrees here so my fingers were little icicles.
For me getting it out was fairly easy but getting the new one back in was a giant PITA!
I have a 99 silverado the 4x4 switch has no lights, i have replaced the switch itself, checked fuses and cleaned the groud cables and the new switch still dont light up. Could the tccm be the problem?
@Nickerson No, it's most likely the Shift Motor on the transfer case. It's a common problem with GMs. You can pull the motor. It can also be done without moving the forward drive shaft. Once off you can turn the spine with a pair pliers to ingage or disengage 4x4 wheel drive. Usually it will display 4x4 service needed or something to that point on the dash. Sometimes the 4x4 button or 2wd will blink.😎👍🍻
I'm having some issues trying to find my tccm i have a 99 suburban 2500 I'm pretty sure it's up underneath by the steering column truck keeps wanting to go in and out of four-wheel drive and none of the lights come on bought a new switch and and everything four-wheel drive service switch comes on 😊
That wouldn't be a TCCM problem. That sounds more like a 'Control Motor' issue. It's located on the transfer case left side (driver's side). It can be removed without moving the forward drive shaft. To check, pull the control motor (while in 2wd engine off) and turn the shaft in the transfer case, start the truck in neutral. After starting, See if it goes in 4wd. If your display is say 4wd needs service, it's the problem. It's quite common on GMs.
Do you think if i replace mine on my 98 bravads it will fix the issue i have i jack it up and the tires are spinning at 15mph the front tire starts sinning then i hear 4 clicks coming from the interior and my service 4wd light comes on
Doses it ingage and disengage? (In 4x4). On GMs it's typically the "Shift Motor" on the transfer case. The TCCM Rarely goes out. Typically it's the Motor. The Module rarely goes out. You could have a short at one of the pens going into the Module or at the ground source. I Can't remember if the ground source is on the body or the frame. It's Up near the driver's side seat seat on the body or frame.
I Would pull the shift motor off the transfer case and manually. Turn the spine and see if it goes in or out of four wheel. If it does then you have your answer.
@@DocAnkh it engages for a second and you can tell cause the wheel starts spinning with a good ammount of speed and power then i get a service awd light and it instantly stops shift motor turns free same with the spine on the transfer case , im gonna check the ground and try it again
Thank you for taking the time. I've had half a dozen people tell me I'm nutz because I don't find it behind the pass kick. (99 Tahoe 4dr) I have an intermittent module that lights all 4wd switch lights and the 4wd service light as well as fails to show on the CAN buss when it's out, hoping it's a connection. fwiw I'm subbed
Hi Scott, hope you got it resolved. Usually if all the lights light up and 4wd service light is on, its the external shift motor on the transfer case. Its not engaging. Its a common problem.
Yes, they sometimes are behind the right kick panel. I had 2 out in the pasture that had the module located there. I have since sent them on to the junk yard. I have had people say to me you don't know what you're looking at. 1 of those people got to see with his own eyes. Lets just say it was priceless.🤣😎👍🍻
@@DocAnkh Got it taken care of not long after I posted. Bad TCCM which is way up under the driver side dash. Working well now. Thanks!
Is replacing the TCCM out with the old and in with the new or is there programming that needs to happen. Asking for a ‘00 suburban 2500
Sorry, I'm sure you already got your answer but, no- it does not need to be programmed.
Also. This module going bad caused my transmission to shift erratically- it would short shift gears and lock the converter up. I’d be in overdrive at 15 MPH, bogging down the motor hard. It was an intermittent issue, unplugging the orange plug here made the transmission shift perfect, but obviously I lost 4WD doing that. Bought a new box off eBay and installed it- ended up removing a DORMAN box out of the vehicle, which means at 250k miles that this is at least the second time it’s been replaced.
Is this my problem I have a 4.8 that rpm huts between 40 and 55 jerking until I get over 55
Thanks, very helpful video.
Thanks man team player love it
Great video thanks I had a hell of a time trying to find it.
Yes I replace mine and it lasted about 2 weeks and it is out again do you know what's killing them
Hi Timmy, Hope you got it resolved. If your still having issues with it, it could be a number of different things. Reply back to me and I'll see if I can help you further.
Thanks. Just what I needed.
My 'service 4wd' light came on. Like a dummy I put it in 4hi. Now the truck will go into 4l, auto 4wd, and of course 4hi, but WILL NOT go into 2wd.
I tried checking fuses, unhooked battery, etc with no luck.
Any info is appreciated
You sometimes can go back and forth from neutral and park while hitting 2wd. That sometimes will at least get you back in 2wd. The problem is in your 4x4 shift motor. Its a very common problem. Its located on transfer case next to the forward drive shaft (driver's side). You can remove it without removing the drive shaft. If hitting the button does'nt work, you have to remove the shift motor and manually turn it back to 2wd. The "Service 4wd Soon " light will not go out till replace shift motor. Driving awhile without the shift motor in it will not hurt anything if you need time to buy the new part. 😎👍🍻
Was your module making a clicking sound by chance?
Mine makes the clicking sound your referring to. Then after 2 attempts at
trying to switch modes, it sets the 4hi light and message center says service 4wd. Is that what yours was doing as well? Why was the fix?
@@mark98070 mine was clicking like it had a glitch in the module . And I was unable to change the modes from 2 high to 4 low or 4 high. I replaced the module and then it got rid of the problem. I am now able to switch modes
@@mark98070 yes mine also had the service 4 wheel drive. When I replaced the module it got rid of the message as well
Sounds that you need a shift control motor. Its located on the transfer case upper driver's side. There are plenty of videos that show the removal and install, it also can be done without removing the forward drive shaft. Its a very common problem with GMs. 😎👍🍻
Thats awesome you got it, but it may have been just been a ground problem. 😎👍🍻
Ey thankyou
There is you like👍 and a new suscriber
Thanks man I have no signal on my brown wire that should be key on hot to the front actuator. Their is a splice around the module so this video is exactly what I searched for.
What was the symptoms for your module replacement? My transfer case switched and front drive shaft starts spinning but front actuator which is new doesnt engage 4hi just flashes. No service 4wd light or codes
Did replacing the tccm fix your problem? I’m having the exact same problem
@@brianmellard5886 Dude the snow went away so I stopped trouble shooting lol. Happens every spring! I get into it than give up when the snows gone. But I’m getting ready to replace transfer case it’s clicking and crunching so I’m going to try checking the signal into the tccm and out of it. If it doesn’t work myself and my coworker came up with the idea we will just run a hot wire right to the front axle actuator. So I’m theory when I press the 4wd high button it should work
@@brianmellard5886 I’ll let you know what I find at the module when I access it. But since everything else is working adding a toggle switch just to send power to actuator rather than the TCCM doing it should work.
Mine is a 2000 Silverado and it’s not there
Others asked, but I haven't seen an answer,,, why did you change yours?? Is clicking an indicator it is bad?? Is there other reasons it would click???
For me it was because I had service 4wd warning light on at all times and the lights on the 4wd switch didn't work and you couldn't switch to any of the drive modes. I replaced the switch first because I have seen some say that is the problem. The switch is inexpensive I think I paid $15 for a knock off on eBay but that wasn't my problem. So I replaced the TCCM and it resolved my issues. I also had a 20a fuse under the hood labeled ATC that kept blowing. Replacing my TCCM has resolved that issue as well.
@@stopthenonsense971 thanks for getting back yo me! I am wondering if the module in the dash is bad! I am going to swap it out with my sons truck before I go further! It clicks a lot, and the truck needs to warm up in order for the switch to work, the trouble light to go off, as well as able to change from one to the next. I will let everyone know once i am finally got it fixed!
@@stopthenonsense971 hello I just have the same issue that you have with my Silverado 2000, but I changed the switch already but I keep getting all the lights on, and it does not do anything, my question is if you had to program the TCCM, with a computer or you just replace it with a used one or a new one. Thank you in advance.
@@jesuswheresanchez4868 I just replaced it
why are you changing the module?
Lock up issue
If it's not disengaging or not going into 4x4 drive it's the shift motor on the Transfer case. You go under and turn the spine with a pair of pliers. It's OK to pull it and run the vehicle until your ready to replace the shift motor. It's a common problem with GMs. Sorry for only getting back to you now. TH-cam didn't notify of your comment.😎👍🍻
Buy a head flash light