R129 Electrical Gremlins-No wipers, SRS light, flashers inop...

[atomix8]

Hey folks, long time member on the Diesel side, finally pulled the trigger on the R129 I've wanted since I was 7 years old.

Let me know if I should move this over to the Tech forum.

1999 SL500 from the south, very nice condition, bought with the convertible top puking hydraulic fluid. Everything (else) worked when I bought it. On the 900 mile drive home to Maryland, the wipers won't work and it's raining heavily. Then the blinkers only indicate left, no matter the position of the stalk. Noticed the seat, steering wheel and mirrors will no longer adjust. Sometimes the stereo would turn off when using the blinkers. High beam flashers don't work. Cool.

Got the car back to MD, pulled all they hydraulics for a Klaus rebuild (just installed them), and started tackling projects on the car. I did a lot of searching, and found a good number of others with similar issues, see my crosspost:
https://www.benzworld.org/threads/srs-light-wipers-headlights-indicator-stereo-seats-problem.2380937/

A lot of these issues seem to happen on my 1999 model year, but I have yet to see a definitive solution. I bought two used convenience relays, have cut open my original to look for issues, but I still have the same symptoms. When I try to use the wipers there's a small groan from the relay. With all this fiddling around, I did get the wipers to work briefly once...and then not again. So I believe the wiper switch and motor are functional.

I have also tried removing fuse #13 (for the convenience relay). This will allow the blinkers to work like normal, the SRS light doesn't come on (at all, it's on fuse #13), but the wipers won't work either. Oddly, if I try to use the wipers without #13, the blinkers go back into left blinker only mode for a few seconds or clicks of the blinker...and then will return to normal operation.

What should I be looking at next???