1995 - 2002 GM OBS Truck Cruise Control Thermal Disengagement Repair (Chevy & GMC)

In this video we will diagnose an intermittent cruise control problem that is tied to high outdoor ambient air temperatures. A seasonal problem when its hot outside that is due to an aging electronics defect resulting in random disengagement, intermittent cutout, or failure to engage at all depending on the outside weather temperature conditions.
The truck illustrated is a 1998 Chevrolet K2500 Cheyenne with the 5.7L vortec engine option, but the procedure and part numbers I share with you will be the same for any 1995 thru 2002 GMT400 generation OBS truck or SUV. So Chevrolet, Cadillac, and GMC for Tahoe, Yukon, Suburban, Silverado, Cheyenne, Escalade, Sierra, and W/T across C1500, K1500, C2500, K2500, C3500, and K3500 weight ratings.
The eBay and Amazon search links below are paid links, for which I may be compensated and earn a commission, if you choose to buy the parts and tools shown in this video thru them:
GM 25315088 (supersedes GM 25314414, GM 25169208, GM 25163330, GM 25140760, and GM 25111708) cruise control module: ebay.us/pNpI1c
GM 15734164 cruise control throttle cable: ebay.us/tx28db
Permatex 81158 black adhesive sealant: ebay.us/l437rR or amzn.to/3Rsfspn
DeoxIT Gold G5: ebay.us/Pml4r7 or amzn.to/3XnwYP7
And if I've saved you some $$ here, consider some coins for the coffee tip-jar! ko-fi.com/drshock
1995 1996 1997 1998 1999 2000 2001 2002
Chapters:
0:00 - Problem overview
1:28 - Removing the cruise control module from the firewall
3:59 - Partial disassembly of the cruise control module
14:39 - PCB inspection
18:06 - Reflowing PCB solder points
20:08 - Post repair PCB re-inspection
20:53 - Reassembling the cruise control module
25:14 - Reattaching the cruise control module to the firewall
27:50 - Test drive results and thermal imaging
#drshock #obstruck #obstrucks #gmt400
Disclaimer: DrShock, the alias for the human content creator for this TH-cam channel, is not responsible for any damages, injuries, losses, or liabilities associated with any repairs, upgrades, or maintenance performed on yours, or any other, vehicle whatsoever. No warranty, express or implied, is made as to the accuracy or completeness of any information provided within this channel. Viewing and using the “as-is" information of this channel is totally at your own risk. Always wear personal protection equipment and follow appropriate vehicle manufacturer service manual guidelines with original manufacturer parts only when performing any repairs, upgrades, or maintenance upon any vehicle.

[@ED-ti5tc]

I went to the salvage yard to get another one. I kept my original one. Great video! Thanks

[@creverett9]

Hi I have a question, say you weren't able to notice any physical disrepair to the board (for example cracked solder joints, bad capacitators, broken traces) how you you more forward in diagnosis to make a repair to the component? I am interested in trying to learn how to repair electronic modules and am curious what could be done to learn how to fix. I have the original Delco radio out of my 2006 Silverado (I've since replaced it with a more modern touchscreen pioneer head unit) but I've always wanted to fix it and maybe reuse it for like a shop radio but i cant find any damage to the board so there's likely a failed component somewhere (concern was no sound out put all other functions normal)

[@DrShock]

It's really not cost effective to do board level repair on a three decade old automotive module. Especially since many, if not all, of the ICs Delco (and later Delphi) used are going to be proprietary and _unobtainium_ commercially. For something _easy_ you could test for shorts to ground on the capacitors and resistors, and you could do a diode test on each of the diodes and transistors. You could test for continuity to voltage and ground at each of the ICs (presuming you could determine the pinout in the absence of a datasheet), each leg of the harness connector, and each of the bridge connector pins. But I'd say that's about it, and I wouldn't even go that far when you can just pop in a replacement from the salvage yard for $15 or so.

[@erichwise7734]

As always an excellent video. Would potting help sustain the board, or retain more heat?

[@DrShock]

Thanks. Due to the electro-mechanical aspect of the module resulting in an open space requirement, potting would not be possible. But the board was sprayed with a clear _conformal coating_ for protection from the elements originally by Delco.

[@creverett9]

@@DrShock Which coating did you use?

[@DrShock]

I did not need to re-apply any coating as the solder reflow did not sufficiently disturb the factory original one to be a concern.

[@Milkmans_Son]

Would it make sense to put a small dab of Superlube Synthetic on those gears (Delrin or whatever they are)?

[@DrShock]

Something non-petroleum based, safe for nylon based materials could be ok. I chose to leave it be as there did not appear to be any applied originally as well as no cosmetic signs of wear present.

[@Tomcat71]

I have a 91 and the cruise interferes with the ignition .. causes the ignition cut out like you just turned the key off and just blew up the new muffler I installed.