All exterior lights turn off when I use the turn signal switch?

Hello,

This will be one of two items that are malfunctioning, either the main body ECU or the combination meter, to be sure which one we need to do a CAN scan which is easy, you can get a CAN scanner (Controller Area Network) from Amazon.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

and

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Here is a list of CAN scanners starting at about $25.00 on Amazon:

https://amzn.to/3DBMlc7

I have also included the location of the main body ECU, which is what I am leaning towards, and the exterior light wiring diagram so you can see how the system works. You can get a rebuilt unit that is preprogrammed by searching Google or eBay. Please let us know what happens.