2015 suburban weird issues in the rain

[Austin19]

I have a 2015 suburban and only when it rains does the instrument gauge needles fall and the anti theft light comes on and then it won’t let you turn it on once you turn it off. When everything finally dries out, it drives just fine with no issues. I have already replaced the bcm and done the g218 foam removal, I also cleaned up the ground behind the front tire. I also have a service side detection system light. Any advice would help!

 

[Geotrash]

I have a 2015 suburban and only when it rains does the instrument gauge needles fall and the anti theft light comes on and then it won’t let you turn it on once you turn it off. When everything finally dries out, it drives just fine with no issues. I have already replaced the bcm and done the g218 foam removal, I also cleaned up the ground behind the front tire. I also have a service side detection system light. Any advice would help!

Welp, you're gonna have to move to Arizona or Nevada, I reckon.

Or...can you give us just a bit more info? Specifically, what codes does it throw during or immediately after such an event?

My bet is that you have a wire or a connector that's getting wet and shorting to ground. The only way I know to diagnose this is to break out your meter when you're experiencing the problem and test every circuit in the fuse box for shorts to ground, followed by the ECM and BCM harness connectors. You can also look for physical damage in the harness where it rubs against any metallic surface.

A competent shop should be able to diagnose this for you also. My local indy shop is particularly good at electrical diagnosis, for example.