A lot of times it's the single wire connector (grey)that jumps from the 3 wire plug-in not getting a good connection. It will cause the battery light to come on.
This was what went wrong on mine. Battery light flickered once during a ~20km trip, when I started heading home on the return trip the light came on solid. Did the diagnostic steps in this video and still had 14.71v at the battery, a little less than 12v at the 1st and 3rd pins on the 3-wire plug and my fuse was fine. So I pulled the 1-wire jumper plug and tightened the contact inside. Plugging it back in - my battery light is out. My plug is damaged though (from before), probably during a previous alternator replacement. I guess I better find a new one before it wiggles loose again.
OMG I replaced alternator@battery still out putting 12 volt,,,it was a 10 cent 20 amp blown fuse,thank you sooo much watch 20+ videos gone on Ford F-150 forms with zero luck,will alternator and battery are good for a while now lol
Also in addition check the thick red and black wire on back of alternator for corrosion if so clean accordingly with wire brush and trace that same wire up to the fire wall and take a loose them connections as well and check and clean corrosion
Or you can take it to Indian River battery in Vero Beach Florida and then we build it put all new parts I mean American made like a brand new alternator that's what I'm going to do tomorrow
My Ford F150 1997 i changed the battery 🔋 after 2 years. After i start it and ride good but asoon as i stop given gas ⛽️ the battery light turns on. But when i gave i reff, it light goes off. What could it be the alternator needs to replace or something else?
The first thing I would do is put meter across the battery terminals to make sure the proper 14V charge voltage is present when the vehicle is running.
wish i watched this before i replaced the alternator. my 20a fuse was blown. oh well, it was the original alternator and my truck has 200k miles so ill just keep the new one on it.
Nice vid!!! I have a battery light that comes when the engine RPM is below 1500 RPMs. It goes out above 1500 RPMs. I already replaced the 6 year old battery today and it didn't fix it. I was at the hunting cabin and didn't have any tools with me so I was over the barrel. I was hoping for a simple fix. The truck is 2003 F150 and the original alternator (18 yrs old). Below 1500 RPMs and light on....voltage at the battery is 11.7-something. I'll check it again tomorrow with the light off (above 1500 RPMs) and see if the voltage at the battery is somewhat normal. If it is normal above 1500, I'm thinking it's the alternator. Also......FWIW....I've never had good luck putting AC Delco (GM) parts on that truck (a Ford). I (the repair shop actually) went thru 3 AC Delco pitman arms failing/wearing out and I finally told them to put on a MOOG part. From previous experience with AC Delco I wouldn't have put that AC Delco alternator on a Ford....but that's just me.
@@TheOriginalMechanic ....Glad to hear yours has been working good. No more battery light on my end. The light consistently going on/off based on engine speed was the first solid clue it was the alternator.
My 2005 F-150 battery warning light is on/off after I did this......I had to jump/charge a battery on my riding mower, 12v. Used my truck, unstarted. Mower started but would shut down if I removed jumper cables. So, I let it charge for about 10 minutes, never starting my truck. Removed cables and mower stayed running. Would this affect the alternator? Thanks for any advice.
@@TheOriginalMechanic That's what I thought but it still flashes the battery warning light, two days later. I made a 1.5 hr trip and thought that would be enough to recharge. I'll give it one more day. Thanks for the reply!
I did exactly what you did but didn't preform the voltage test toward the engine, is that why the new alternator went belly up and the battery light cam on. What did I miss?
I have a 2001 F-150. Just purchased the truck. The battery light just came on the other day. I had a parts store test the battery and alternator and both came back ok. I get 14.7 volts consistently even with a load. Battery reads about 12.2-12.5 vdc. If I unplug the 3 pin connector off of the alternator while it is running, the light goes out. Any ideas?
Yes. If I remember correctly, it was a loose connection on the single wire connector. See around 4:30 of the video. I touched /moved that wire at one point and all of a sudden the light went out. I believe the connector clip was broken and was not getting a good connection. I haven’t touched it since and light is still out.
Didn’t you have any intermittent rough idling? I have. 2004 f250 5.4 . Batter and alternator are fine. But battery light is on when the truck runs it’s runs fine then rough idles for a few moment thens cleans up then will randomly high idle then drop back down I’m so confused as to what’s wrong. When I first brought the truck home I had it running for like 20 min I shut it off and tried to start it and it was dead I replaced the battery w a brand new one, had advanced auto check alternator and it’s fine. I have no idea what to do
@@TheOriginalMechanic okay thanks so much I’ll start there. Would love to get the truck running properly and give my Silverado a break. I got the best of both worlds lol 5.3 and now a 5.4
Great video, thanks! My 2007 F150 battery light just started coming on but only at idle at a stop light just last night. I put it in neutral and reved it up to 1,000 rpm (idle was 750) and the light went out and stayed out…until the next stop light! It got me home but I’m guessing I’m going to need a new alternator. I looked at Advanced Auto Parts and their prices range from around $100 for a remanufactued to $265 for brand new. The truck has 218,000 mostly highway miles on it, I bought it new and plan on keeping it forever, just to haul hey to the barn, should I spend the extra money for the brand new alternator or is a remanufactured one ok? Also, how many hours of “labor” should I expect to pay a local small repair shop (not the Ford dealership) to install it? Thanks again for doing the great job on that video, now do you have one for the F150 automatic transmission? Mine is skipping a lot when it gets to around 45-50mph.
My only advice on parts like alternators is to put in a name brand. I stay away from the store brands of stores like Napa, Advance Auto etc. I put an AC Delco in my truck. I wouldn't worry if it's new or manufactured either. Thankfully I haven't had to do any transmission work on my truck, aside from changing the fluid. Have an good one and thanks for watching!
Hey Timbo77LR I am experiencing the exact same thing on my 05 with the battery light coming on @ idle and off when it's revved. Was it the alternator?? Cheers
@@zoots15 Yes, it was a bad alternator, I replaced it with a new one and it’s been fine ever since. But now the transmission is acting up! Lots of bucking around 45-50 mph!
@@Timbo777LR Thanks bud. I changed it out today and everything is back to normal. As far as your bucking issue, you may have a bad ignition coil(s). I had similar symptoms a couple of years ago and changed them all out. Problem solved. Hope it works for you! Let me know. Cheers.
@@zoots15 you were right about the ignition coils causing the bucking! My private mechanic (not the Ford dealership) has been changing out the plugs and wires as the coils are now part of each wire, and after installing 3 new ones, bucking stopped. Thanks for the help!
Great vision, very informative. I have a 2004 Heritage Edition with just over 200k (with original Alt), my battery light is flashing off and on, it is not consistently on. At first I checked the battery (650CCA), it was at 11.2 volts engine off. It would not turn over, all I heard was the clicking noise, with the starter not turning. I charged it over night, with a 2amp trickle charger. It was at 13.6 volts and started just fine, showing over 14 volts at the battery with engine running. Since the battery was well over 5 years old I replaced it with a new motorcraft (850CCA). It still shows over 14 volts engine on, the engine did turn over with multiple attempts, but the battery light is still flashing, not consistently on. I did not check the alt other than the battery charging voltage. Any thoughts? Thanks in advance.
I'm helping a friend diagnose his 03 f150 with the same issue. I'll have him review this video and check that fuse. Do you have any idea what the solenoid on the firewall that the alternator wire goes to is for and how to check it if necessary?
This reply is about a year late and I hope you've figured it all out by now. But if you're talking about the solenoid on the passenger firewall, that's the starter solenoid that grounds itself to the firewall and could cause a no start as it's connected to the alternator, battery and starter
Thanks for the video. It showed me a few more things to check.
You saved me a trip to the mechanic, I forgot about checking fuses.
A lot of times it's the single wire connector (grey)that jumps from the 3 wire plug-in not getting a good connection. It will cause the battery light to come on.
Will that cause a flashing battery light?
@@noidnomis
Yes.
This was what went wrong on mine. Battery light flickered once during a ~20km trip, when I started heading home on the return trip the light came on solid.
Did the diagnostic steps in this video and still had 14.71v at the battery, a little less than 12v at the 1st and 3rd pins on the 3-wire plug and my fuse was fine.
So I pulled the 1-wire jumper plug and tightened the contact inside. Plugging it back in - my battery light is out. My plug is damaged though (from before), probably during a previous alternator replacement. I guess I better find a new one before it wiggles loose again.
Great video and very detailed
Thank goodness I found this before trying to replace my alternator... 20a fuse!
Fixed the problem! Thank you for a great video!
You led me to the same problem you had. Thanks!
OMG I replaced alternator@battery still out putting 12 volt,,,it was a 10 cent 20 amp blown fuse,thank you sooo much watch 20+ videos gone on Ford F-150 forms with zero luck,will alternator and battery are good for a while now lol
I was jump starting one of my pos Hondas and got a battery light on my f150. Still charging tho. Just has a light on dash. Haven’t dug into it yet.
I wished that was my problem. Battery is good, alternator is new.........light still on. Gotta check that fuse, lol.
Also in addition check the thick red and black wire on back of alternator for corrosion if so clean accordingly with wire brush and trace that same wire up to the fire wall and take a loose them connections as well and check and clean corrosion
Here in Kentucky I had mine rebuilt for $150.00 and beefed mine from 95 amp to 140 on a 96 F250 7.5 460 big block . Much better price than new one.
That was AWESOME !!!!! I'm going to try to change the alternator in my 2000 Ford Expedition, Eddie Bauer . You have Made My Day !!! 😉
Or you can take it to Indian River battery in Vero Beach Florida and then we build it put all new parts I mean American made like a brand new alternator that's what I'm going to do tomorrow
Mine battery light stays on when engine off
I have no excitation voltage but the fuse is good. what all could be the issue?
Thx you Sir!!!!!
Thank you blessings
I changed my alternator and my battery and my light isn't going away and it's having problems to start in the mornings
Starter
My Ford F150 1997 i changed the battery 🔋 after 2 years. After i start it and ride good but asoon as i stop given gas ⛽️ the battery light turns on. But when i gave i reff, it light goes off. What could it be the alternator needs to replace or something else?
A slipping belt comes to mind first. If that isn't' it I would suspect the alternator.
i had same burning smell in my ford freestyle and and now it wont start
please help
If the battery light is on that will help confirm that you need an alternator.
My lights would dim and Surg a little at idle - then I replaced the belt tensioner and a new belt - that’s when the battery light came on ???
Ok, so I have a new battery and alternator on mine and the battery light is still on. So I guess fuses and connections need re-checked.
The first thing I would do is put meter across the battery terminals to make sure the proper 14V charge voltage is present when the vehicle is running.
i did the same thing as the video with the same results. but after about four hours of driving the battery light came on again and the light went dim.
Great stuff bro
wish i watched this before i replaced the alternator. my 20a fuse was blown. oh well, it was the original alternator and my truck has 200k miles so ill just keep the new one on it.
Could have been an internal short in the alternator. 200K? You got your money's worth from that one. Mine died at 120K.
Inside or exterior fuse
Nice vid!!! I have a battery light that comes when the engine RPM is below 1500 RPMs. It goes out above 1500 RPMs. I already replaced the 6 year old battery today and it didn't fix it. I was at the hunting cabin and didn't have any tools with me so I was over the barrel. I was hoping for a simple fix. The truck is 2003 F150 and the original alternator (18 yrs old). Below 1500 RPMs and light on....voltage at the battery is 11.7-something. I'll check it again tomorrow with the light off (above 1500 RPMs) and see if the voltage at the battery is somewhat normal. If it is normal above 1500, I'm thinking it's the alternator. Also......FWIW....I've never had good luck putting AC Delco (GM) parts on that truck (a Ford). I (the repair shop actually) went thru 3 AC Delco pitman arms failing/wearing out and I finally told them to put on a MOOG part. From previous experience with AC Delco I wouldn't have put that AC Delco alternator on a Ford....but that's just me.
So far the alternator has been working great. Your issue is a little odd but does suggest a failing alternator.
@@TheOriginalMechanic ....Glad to hear yours has been working good. No more battery light on my end. The light consistently going on/off based on engine speed was the first solid clue it was the alternator.
Would i still be able to change the voltage regulator even if the slip rings look like that still ?
I don't know how to answer that except to say alternators aren't that expensive if can do the job yourself.
@TheOriginalMechanic gotchu and it's cheaper doing my self nowadays
My 97F150 third alternators still not charging wiring was missing so no field fuse how does it wire in
I don't profess to being a wiring expert. I would look at a wiring diagram of the circuit and try to duplicate it.
Replaced my alternator on my 99 and battery light still on?
If you haven't yet, check for excitation voltage input to the alternator. My coverage of that starts at 2:03
same problem i'm having... i have just put in a new alternator yesterday and still the battery light still on.
@@ramboperkins7213 have you fixed it ? if so what was the problem
Teacher, what country are you from?
USA
exelente trabajo
My 2003 f150 did the samething it was a 20 amp fuse but my light is still on and I'm charging at 14.51
did u find the problem, mine is charging, but light stays on
My 2005 F-150 battery warning light is on/off after I did this......I had to jump/charge a battery on my riding mower, 12v. Used my truck, unstarted. Mower started but would shut down if I removed jumper cables. So, I let it charge for about 10 minutes, never starting my truck. Removed cables and mower stayed running. Would this affect the alternator? Thanks for any advice.
I don[t see how that would hurt your alternator. Might take a bit of charge off your truck battery, but that's it.
@@TheOriginalMechanic That's what I thought but it still flashes the battery warning light, two days later. I made a 1.5 hr trip and thought that would be enough to recharge. I'll give it one more day. Thanks for the reply!
I did exactly what you did but didn't preform the voltage test toward the engine, is that why the new alternator went belly up and the battery light cam on. What did I miss?
I'd look for the excitation voltage or a blown fuse in that circuit.
I have a 2001 F-150. Just purchased the truck.
The battery light just came on the other day. I had a parts store test the battery and alternator and both came back ok. I get 14.7 volts consistently even with a load. Battery reads about 12.2-12.5 vdc. If I unplug the 3 pin connector off of the alternator while it is running, the light goes out. Any ideas?
Did you ever figure it out?
Yes. If I remember correctly, it was a loose connection on the single wire connector. See around 4:30 of the video. I touched /moved that wire at one point and all of a sudden the light went out. I believe the connector clip was broken and was not getting a good connection. I haven’t touched it since and light is still out.
Didn’t you have any intermittent rough idling? I have. 2004 f250 5.4 . Batter and alternator are fine. But battery light is on when the truck runs it’s runs fine then rough idles for a few moment thens cleans up then will randomly high idle then drop back down I’m so confused as to what’s wrong. When I first brought the truck home I had it running for like 20 min I shut it off and tried to start it and it was dead I replaced the battery w a brand new one, had advanced auto check alternator and it’s fine. I have no idea what to do
I meant did you have* not didn’t you have
Also no check engine light
@@juliorobles5696 I would focus on fuel delivery components such as fuel pump, filter, injectors. Idle air control valve maybe?
@@TheOriginalMechanic okay thanks so much I’ll start there. Would love to get the truck running properly and give my Silverado a break. I got the best of both worlds lol 5.3 and now a 5.4
Great video, thanks! My 2007 F150 battery light just started coming on but only at idle at a stop light just last night. I put it in neutral and reved it up to 1,000 rpm (idle was 750) and the light went out and stayed out…until the next stop light! It got me home but I’m guessing I’m going to need a new alternator. I looked at Advanced Auto Parts and their prices range from around $100 for a remanufactued to $265 for brand new.
The truck has 218,000 mostly highway miles on it, I bought it new and plan on keeping it forever, just to haul hey to the barn, should I spend the extra money for the brand new alternator or is a remanufactured one ok? Also, how many hours of “labor” should I expect to pay a local small repair shop (not the Ford dealership) to install it?
Thanks again for doing the great job on that video, now do you have one for the F150 automatic transmission? Mine is skipping a lot when it gets to around 45-50mph.
My only advice on parts like alternators is to put in a name brand. I stay away from the store brands of stores like Napa, Advance Auto etc. I put an AC Delco in my truck. I wouldn't worry if it's new or manufactured either. Thankfully I haven't had to do any transmission work on my truck, aside from changing the fluid. Have an good one and thanks for watching!
Hey Timbo77LR I am experiencing the exact same thing on my 05 with the battery light coming on @ idle and off when it's revved. Was it the alternator?? Cheers
@@zoots15 Yes, it was a bad alternator, I replaced it with a new one and it’s been fine ever since. But now the transmission is acting up! Lots of bucking around 45-50 mph!
@@Timbo777LR Thanks bud. I changed it out today and everything is back to normal. As far as your bucking issue, you may have a bad ignition coil(s). I had similar symptoms a couple of years ago and changed them all out. Problem solved. Hope it works for you! Let me know. Cheers.
@@zoots15 you were right about the ignition coils causing the bucking! My private mechanic (not the Ford dealership) has been changing out the plugs and wires as the coils are now part of each wire, and after installing 3 new ones, bucking stopped. Thanks for the help!
Whats the stupid year ?
His description says 2000 however this is exactly the same for 1997 to 2003
Great vision, very informative.
I have a 2004 Heritage Edition with just over 200k (with original Alt), my battery light is flashing off and on, it is not consistently on.
At first I checked the battery (650CCA), it was at 11.2 volts engine off. It would not turn over, all I heard was the clicking noise, with the starter not turning.
I charged it over night, with a 2amp trickle charger. It was at 13.6 volts and started just fine, showing over 14 volts at the battery with engine running.
Since the battery was well over 5 years old I replaced it with a new motorcraft (850CCA).
It still shows over 14 volts engine on, the engine did turn over with multiple attempts, but the battery light is still flashing, not consistently on.
I did not check the alt other than the battery charging voltage.
Any thoughts?
Thanks in advance.
I think you might have a poor connection on the small alternator harness. Take a look at the comment below .
I'm helping a friend diagnose his 03 f150 with the same issue. I'll have him review this video and check that fuse. Do you have any idea what the solenoid on the firewall that the alternator wire goes to is for and how to check it if necessary?
Those solenoids are for the 4WD system.
This reply is about a year late and I hope you've figured it all out by now. But if you're talking about the solenoid on the passenger firewall, that's the starter solenoid that grounds itself to the firewall and could cause a no start as it's connected to the alternator, battery and starter
I want to study with a teacher
Problem with me I have a good alternator now what 🤦🏼
Need to verify the presence of the excitation voltage next. The alternator won't produce charge current without it. 1:52