QuestionQUESTION: We have just recently had the buttons for the power doors located in the middle row (on the pillars) stop working - at almost the same time. Manual opening and closing works, key fob works and overhead console buttons work, just the rear buttons have failed. I opened up the passenger side pillar, and cut the wires to see if it was the physical button but it still doesn't respond when connecting the wires. One thing we did find is if the lights shut down with the door open (took me some time fiddling with the pillar and looking at the tracks) and you hit the button, the lights will come back on. Tells me that something is getting the signal that the button was pressed, it just isn't engaging the motor. Any ideas what may be going on? Thank you!
ANSWER: Hi Donny,
Have you check fuse 31 in the power distribution box under the hood? That is the most obvious reason for the B-pillar switches to fail on both sides. Otherwise, the body computer which oversees the door function has to be considered as the source of the problem. However there is no obvious reason than the fuse for both the switches to fail to operate while the power doors will operate via the fob and manual control. Each door switch has assigned wires uniquely to the bcm and so I would not believe the pillar switches would be the cause if both failed simultaneously. So check that fuse and let me know what you find. The fuse is 40 amp and located inboard of the rear blower motor relay.
Roland
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---------- FOLLOW-UP ----------
QUESTION: Thanks for the quick reply Roland, I checked fuse 31 and it is good - I swapped it with another just to be sure. When removed, the motors for both doors are completely stopped via key fob, overhead button etc.
AnswerHi Donny,
The two B-piilar switches are independent and merely ground two separate pins at the body computer (through intervening resistors built-in to each switch so it won't read a dead short). The body computer then activates the separate door power modules in the doors. Because those modules will respond to the fob and to manual requests, the problem has to be a failure of the bcm to recognize or act upon the grounding signals from the separate switches. The fuses for the bcm are 14, 19, 24 so those would be reasonable to check.
The wire from the right switch (violet/yellow) goes to pin 12 of C3 plug at the bcm, while the left switch wire (violet/dark green) goes to pin 18 of the same plug. You could verify that the grounding is occuring when you activate the switches, as seen at the bcm pins. The C3 plug has a black shell/white interior.
The two switches are wired to separate ground points on the body so it is doubtful that the grounds for the switches are both faulty, but you could check just to be sure. The ground wires are black/yellow and black/dark green, respectively.
I wish there were some other more obvious reason, but I see no others.
Roland
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