Abs & traction control light

[hwcian]

I discovered today that the ABS & TCS lights are tied in to the brake bulbs in the rear lamps. When the brake portion of the 3057 bulb is out in both rear lamps it triggers the ABS/TCS light. If you pull one it will not come on but both it will. So for whatever stupid reason GM tied the ABS system to brake light bulbs check them first before going forward to any other part of the ABS.

I changed a bad passenger side wheel bearing and thought that is what was triggering the light but R&R did not remove light. That is when I discovered my rear brake lamps were not working but the tailights were so I swapped the bottom tail lamp bulbs with the top and now all is good. This is crazy to think that if I lose my bulbs in the middle of winter and roads are crazy I have no ABS? Seems awfully risky for GM.

Thanks,
Ian

[esonsteby]

I had the same problem with a 2001 Montana. Rear brake lights (top one of the 4 in each bank) did not work. Service Traction Control idiot light came on in the message center. (and the TCS remained off and did not work at all!) The upper hatch brake light did work. I swapped the 3057 bulbs from bottom to top in each of the 2 rear assemblies and the Traction Control started working! (fyi, the top bulbs were good.) Like all of Murphy's laws, this happened during a snowy/icy stretch. We all know that without TCS working the Montana/Venture/Sillohette suck in the snow.

I have read that the connector assemblies to each of the rear lights may be the culprit, however I found no evidence of melted/scorched connectors. I am, however, going to solder an additional ground lead from each of the connectors to the frame. Seems that the Montana/Venture/Sillohette have chronic grounding issues.

Glad it was a simple issue and not the wheel bearings/sensors which I had suspected. Hope this helps anyone with a similar issue.

Erik