I am having problems with the cruise control on my 2004 Buick Rendezvous, and specifically with the cruise control release switch. When attempting to activate cruise control, no light is displayed on the dashboard and cruise control does not work at all. Here is what I have found and what I have tried:
-I verified that all taillights and brake lights are working correctly.
-I verified that the cruise control fuse is working and the cruise control module is receiving power.
-I verified that the cruise control switch (off/on/resume/set) is working correctly, as it is sending appropriate inputs to the cruise control module.
-I verified that there are no errors in the PCM inhibiting cruise control.
-Replacing the cruise control module had no impact, so I am convinced that the problem does not lie in the cruise control module.
-I found that the cruise control release switch was bad (fails open) and replaced it (twice!), but each time cruise control worked for only 5 or 10 seconds before cutting out. After this, the (new) cruise control release switches were found to have failed.
What could be causing my cruise control release switches to immediately fail? How can I try to track down what the underlying problem is?