ryanstapes
TYF Newbie
- Joined
- Aug 17, 2012
- Posts
- 1
- Reaction score
- 3
2003 Chevy Tahoe with 145,000 miles.
I joined this forum to share my findings and hopefully help someone out in the future. I had an intermittent electrical issue for the past year, that I tried every solution that I could find online, but it never fixed the problem.
Symptoms:
1. Sometimes if the vehicle was running for a long period of time or even going over large bumps in the road it would trigger the following things to stop working: fuel gauge, oil pressure gauge, battery gauge, temp gaugue, radio, windows, door locks, key fob, A/C compressor (the blower still worked). The abs light and E-brake light would display on the instrument cluster. The information center would display “Unknown Driver”.
2. The issue also would occur on occasion while not running and would cause the vehicle not to start. All the conditions listed above were the same, but the addition of having it not start was the big kicker. It still cranked and would start for a second, but then died, just like the theft deterrent would do. This would happen to me after driving it, stopping for a short period of time, then trying to start it again (just running errands) or if it was a hot day( >80F) and the sun was beating on it for hours.
Things I tried:
In my research I found plenty of people that had the same symptoms as me and the things I tried were: Inspecting and cleaning all the grounds, checking for power to all the modules, relocating the black with yellow stripe wire going to the back of the engine block, pinched data wire in the center console, chaffed wires under the driver seat, reseating connectors, bypassing the theft deterrent at the ignition, I also replaced the ignition switch.
Testing:
I had a tech2 with limited knowledge for using it, but mostly just used it to see if I had communication with the modules. When the truck was not having issues I could not get communication with the radio or HVAC, but everything else showed up. If the truck was experiencing the problem the tech2 would not even establish communication. I then used a scope to trace the data voltage signal from the DLC connector, it showed a good looking square wave that peaked at 7 volts, so no issues there. I also removed the jumpers from splice packs 205, 206 & 207, to check the data signals of the individual modules, again everything check out here, 7 volt square waves. I noticed when I put the jumper back in sp205, my door module stopped working, so I messed with it then the radio stopped working and so on. It was very difficult to get everything working at the same time.
Solution:
I found the problem was the jumper for the class 2 serial data wires at the splice pack connector sp205. It’s a 12 pin connector under the dash to the left of the BCM, and it’s not easy to get to. It has a white plastic cover on it that holds in the metal jumper. All I did was remove the jumper put a small bead of solder on each pin of the jumper to build up the width of the pin. I checked the modules with the tech2 and now had communication with all of them. I guess the terminals of the connecter had lost some of their spring and were barely making a connection. Heat was the biggest trigger of the problem, so the poor connection was creating a resistance resulting in heat being generated.
Sorry about the long write up, but hopefully this helps someone out.
I joined this forum to share my findings and hopefully help someone out in the future. I had an intermittent electrical issue for the past year, that I tried every solution that I could find online, but it never fixed the problem.
Symptoms:
1. Sometimes if the vehicle was running for a long period of time or even going over large bumps in the road it would trigger the following things to stop working: fuel gauge, oil pressure gauge, battery gauge, temp gaugue, radio, windows, door locks, key fob, A/C compressor (the blower still worked). The abs light and E-brake light would display on the instrument cluster. The information center would display “Unknown Driver”.
2. The issue also would occur on occasion while not running and would cause the vehicle not to start. All the conditions listed above were the same, but the addition of having it not start was the big kicker. It still cranked and would start for a second, but then died, just like the theft deterrent would do. This would happen to me after driving it, stopping for a short period of time, then trying to start it again (just running errands) or if it was a hot day( >80F) and the sun was beating on it for hours.
Things I tried:
In my research I found plenty of people that had the same symptoms as me and the things I tried were: Inspecting and cleaning all the grounds, checking for power to all the modules, relocating the black with yellow stripe wire going to the back of the engine block, pinched data wire in the center console, chaffed wires under the driver seat, reseating connectors, bypassing the theft deterrent at the ignition, I also replaced the ignition switch.
Testing:
I had a tech2 with limited knowledge for using it, but mostly just used it to see if I had communication with the modules. When the truck was not having issues I could not get communication with the radio or HVAC, but everything else showed up. If the truck was experiencing the problem the tech2 would not even establish communication. I then used a scope to trace the data voltage signal from the DLC connector, it showed a good looking square wave that peaked at 7 volts, so no issues there. I also removed the jumpers from splice packs 205, 206 & 207, to check the data signals of the individual modules, again everything check out here, 7 volt square waves. I noticed when I put the jumper back in sp205, my door module stopped working, so I messed with it then the radio stopped working and so on. It was very difficult to get everything working at the same time.
Solution:
I found the problem was the jumper for the class 2 serial data wires at the splice pack connector sp205. It’s a 12 pin connector under the dash to the left of the BCM, and it’s not easy to get to. It has a white plastic cover on it that holds in the metal jumper. All I did was remove the jumper put a small bead of solder on each pin of the jumper to build up the width of the pin. I checked the modules with the tech2 and now had communication with all of them. I guess the terminals of the connecter had lost some of their spring and were barely making a connection. Heat was the biggest trigger of the problem, so the poor connection was creating a resistance resulting in heat being generated.
Sorry about the long write up, but hopefully this helps someone out.
