If the switches are all good and have power, the next concern is a breakdown in communication between the modules. The PCI bus signals the passenger side and opposite.
Basically, the modules are tied together via the a can bus system. CAN stands for computer area network. With it, the manufacturer can tie multiple modules together to communicate with very little wiring. They started using this as there was an increase of computer and modules in the vehicle. It was to eliminate weight from the massive amounts of wiring that was needed.
If you look at the attached pic, I highlighted the bus system between the modules. The way this needs tested is by scanning the CAN bus system. That checks all communications between all modules to see if there is a break down. It should indicate if there is an issue with this situation.
Here is a video that shows how it's done and what can be found doing it:
Let me know what you find or if you have other questions.
I just spoke with the owner of the site about this. He indicated that 9 out of 10 times, the module itself is bad. He suggested replacing that first.
Thursday, July 30th, 2020 AT 1:33 PM