86 Daytona electrical gremlins....

[Lee'sdaytona]

Greetings all! My project log doesn't seem to be getting much attention, so I'll post my question here:





My daytona (86 TI Log stock, with MP logic Module 525 trans) is finally running pretty good, but I am having trouble knowing where to start with the electrical issues.
they are:

1) Radio clock and navigator screen blink when the blinker is on, and they go black when the brake pedal is applied.
2) I am only getting 5 volts to the 4 large bulbs in the taillight bank, so they are very dim. The outer part of the taillamp that uses 194 bulbs, and the center stop lamp work great.
3) The continuous power feed to the radio and navigator is not working, because each time I get out of the car, or restart, it is always new years eve!
4) The radio will turn off when I open the door OR turn on the dome lamp manually.
5) Horn is in-op. I have swapped the horn relay at the fuse box but no go.

All this I believe is related. I have cleaned the grounds: Radio ground, lower left kick panel, lower right kick panel, rear left ground.

There were mice living in the car at one point, but all the wiring I have seen so far looks great inside. The under hood wiring harness is a different story, as its almost completely wrapped in electrical tape. Could this be the area to look first? My thoughts are this is a Positive wire problem and not a ground issue. Clearly, there is not enough voltage to supply all the power.

I found the under hood lamp wire hanging bare with 12 volts that could have been shorting to ground, so I re-wired that and at least I have a working under hood lamp!

I also have this harness I can't figure out where it should go:





As always, your advice is very much appreciated.
http://www.turbo-mopar.com/forums/sh...-S-restoration

[raccoon]

your -ebrake switch is unplugged. but thats no doubt unrelated. I'm thinking a ground problem. the dome light turning off the radio makes me think this. is this the cars original engine harness? when you press the horn do you hear the relay click?

[Lee'sdaytona]

Which ground should I check? Where would this be and what is the best way to check a ground? I know the e brake switch is unhooked, I must have done that because it used to work. Just have to find the wire for it now...what about the dim tail lamps?

[Lee'sdaytona]

Oh, and I assume the harness is the original, but who knows. Good news is I have a harness (under hood) from an 86 Turbo Z automatic in good shape I can swap in, if nothing else to make it look much nicer. Many of the wires at the power module plug are cracked and exposing the bare wire, although none touch eachother. Same at the knock sensor, etc.
-Lee

[minigts]

I have the 85 manuals (not with me I don't think). You really need to get the diagrams and pull the harness from inside the car. I would imagine there are some wires shorting out either somewhere in the harness or maybe behind the fuse box? I'll look around and see if I have some on my portable drive.

[Lee'sdaytona]

I do have the 86 manuals. So your thinking the interior harness and not the under hood? Otherwise I guess I'll have to pull the inside harness

[minigts]

I mean it could be, but the feed goes inside the car and from there most of the issues you're mentioning are inside.

[supercrackerbox]

Does the car have a factory stereo in it, using the factory wiring connectors? I've seen a lot of cars where someone installed an aftermarket stereo, and hacked the living hell out of the wiring rather than buy a $15 install kit. The constant power (memory), switched power, and dimmer (Dome light, door light, external lights) all feed into the stereo harness, so if that's been hacked up, that's where I would start.

If that all checks out, then I'd move onto the headlight switch on the dash. I've had a couple Daytonas where the wires became chaffed and/or burned at that connection.

[Lee'sdaytona]

Ok good points. It was hacked for an aftermarket stereo at some point. I then wired in a factory harness and put the factory radio back in. Maybe I mix matched a wire? I know I used a diagram, because the pigtail I used was from a caravan or something and while the plugs were identical, the wire color code was different. I just replaced the headlamp switch, and all looked ok.

[Lee'sdaytona]

What is the best way to test a ground?
I'm thinking take a long wire from + on battery and check voltage from that direct wire to the ground strap by the radio. Sound like that will work?
-Lee

[Gearhead24-7]

I went thru the exact same thing. Replace your positive battery cable.

[Lee'sdaytona]

Interesting. I might just invest some time in swapping the entire under hood harness, since after all, I have one waiting for it, and many of the wires are cracked on the current one.
THanks,
Lee

[marc]

Lee, check to see if you have 12 volts on all your fuses at the fuse box will everything turned on. All that stuff that is giving you trouble is feed by one red 12 gage wire going into the fuse box and a gray 18 gage fuseable link under the hood to the fuse box.

[Lee'sdaytona]

Gents,
I have still yet to replace the wiring harness, however, besides having to swap a MAP sensor, its been running rather well, the traveler is keeping time and date stored all of a sudden for several months now.
New issue though:
I went to drive it for the first time in like 3 weeks and the battery light started to come on and off. The volt gage would drop to about 11 V, and the tachometer would start dancing in circles and acting all erratic. Can this be a result of an alternator on the fritz? I know when my caravan's alt went bad it just stopped charging...no erratic gages.
Thanks for any input!
-Lee
PS: Other times during my short drive, the battery light went off, volt gage read around 14/normal, and the gage worked properly.