redmund

Very strange things are happening with the electrics in the dash of my car. When my PO removed the original stereo, he hacked off the old wiring harness. Fair enough, I said. I'll figure out what wires were what, no worries. So I found the constant +12v and the switched +12v, along with ground, power antenna and the speaker wires.

Problems start when I actually hook a stereo up to the harness I've soldered into the old wires. Everything is matched up properly, I've checked the diagrams about 20 times. With no stereo connected, I get a full 12v on each of the lines, switched and constant. When I connect the stereo though, both lines sag to 2.5v, and, obviously, the stereo refuses to fire up.

Now, to be honest, when I saw the 12v constant and switched wires, I kinda thought they were a bit thin, especially in comparison to the ground wire that exists there. Is it possible the PO replaced the original wiring at some point with horrible light gauge crap and it just can't deal with the load the stereo is asking for, ending up with the sagging voltage and no power to the head unit?

Any and all help appreciated!

75ohm

Shane,
I went down this path as well and ended up running a 12v constant to the battery...

https://rennlist.com/forums/showthre...ghlight=stereo

75ohm.

KuHL 951

If you are dropping to 2.5V from 12V under load you have a short in the set-up somewhere. I would skip the under dash wiring and run dedicated power feeds. The wiring on these cars is bad but I doubt you would see that kind of drop just from smaller wire size alone.

joejoe

Strangely the small wires did this on the '90 cab also. There is a thicker green wire that is constant (i believe) and a larger red that is switched. I am not sure what the smaller ones do. The PO left the plug dangling under the stereo, but I have no idea what system was in the car originally.

redmund

I have no thick wires, save for the ground wire. I've been rooting around under the dash today, trying to figure stuff out, and my god, you should see the mess that's under here. I've so far found 3 separate antenna wires, 2 of which look like they were just ripped apart, the 3rd was cobbled together from extension leads. Some crazy blue wire with an inline fuse is running alongside the thin green wire for the power antenna, and disappears out the hole in the footwell. This is going to be so much fun!

UncleMaz

+1. I now have a dedicated circuit for both my stereo system and my cooling fans (I just wired a thermal fan switch bypass switch as a precaution). Next is my headlights. The wiring is so weak in the car.