Please help me slay this electrical gremlin!

[tigre]

Hi all, I'm having a bit of trouble and hope someone can help me out. I recently swapped out the stereo head unit in my 2003 Safari, and since then a few things have either stopped working or work sporadically.

Here's the long list of things that are wrong with my van: the rear wiper and rear a/c don't work at all, the clock/radio backlight works when it wants to, the gauge needles flicker a bit (the gas gauge once read empty and the fuel light came on even though I knew it was lying to me), and now the power door locks aren't working right. All the wiring harnesses are connected securely and I've checked fuses and reset the battery by leaving it disconnected for an hour, but it didn't help. I have no clue what's going on here and really don't think these are all isolated incidents. If anyone can help I'd love to hear some ideas. Thanks so much!

[Herbie]

This sounds like a faulty main ground someplace. Battery cables clean and tight? Main grounds good?

There are several in a 2003 - a couple at the top of the engine bay, a couple on the driver's side fender wall area, I think, and a couple more farther down...

[tigre]

Thanks so much! There was a loose ground in the dash below the stereo. The only thing still having troubles is the door lock actuator. The passenger side was already dead when I got it but now I guess the driver's side is too. That one maybe I can just clean it up since it's just now going out.

[CaptSquid]

Check the main battery ground as well. I just found out yesterday that that particular item was at fault for 99% of my electrical woes.