[CBR600RRider]

So long story short, I got a 1988 S15 from my neighbor that sat in a field for a few years. I v8 swapped it and now i'm chasing down some wiring problems I'm coming across.

-I have no power to the radio or any of the dash ( Dummy lights still work but nothing else )
-My light switch turns on the front lights but the rears don't come on.
-Blinkers still work.
-I've checked fuses the only one that doesn't have power is a 5A label INSTA, I checked with a test light on the connector itself and it has no power going to that fuse.
-I took the light switch off and cleaned the contacts, but it didn't help.

Please any help would be wonderful. Thanks!

 

[oldeerslayer]

Did you do the test of the INST fuse holder with the key on? What lights don't come on in the rear? No brake or turn or just the tail and plate lights? Look under the drivers carpet for rotten wires. If it sat with water in there for years it's probably a mess under there.

 

[CBR600RRider]

Did you do the test of the INST fuse holder with the key on? What lights don't come on in the rear? No brake or turn or just the tail and plate lights? Look under the drivers carpet for rotten wires. If it sat with water in there for years it's probably a mess under there.

I did the test with the key on (but truck not started) and the test light didn't hit on INST at all, or the contacts underneath the fuse.
No plate light, or tail lights when I flip the switch. However, if i press on the break pedal my brake lights come on.

 

[oldeerslayer]

Have you tried new bulbs in the back? Running lights in the back are the brown wire. Green is right brake and turn. Yellow is the left. Easy way to remember is if the color has an R in it it's the right side. If there's a trailer connector back there remove it while testing. They can be the culprit.
Instruments are likely a separate issue.

 

[CBR600RRider]

Alright, so maybe it was my poor cleaning skills. But the taillight issue was in fact the switch.
I'm still trying to figure out why the dash doesn't have power ( radio, cigarette lighter, etc..)
The OE did some hack job putting the aftermarket radio on. With jumper wires and splices all over the place.
Does anyone have the original diagram for the radio? I have a new head unit to put in and I might as well clean up everything and make sure that there isn't a short anywhere. Thanks!

 

[oldeerslayer]

The factory wiring diagrams from 88 don't even show the radio.So they aren't any help.
But one of these reverse harnesses should cure the problem. It is designed to repair cut wiring with a factory style connector. Then if you get the matching one for your after market radio it will be plug and play just like it was from GM.

Metra 71-1677-1 (met-7116771) Reverse Wiring Harness for 1978-

Metra 71-1677-1 • Reverse Wiring Harness for 1978-1990 GM Vehicles 12-PIN Factory Radio • Wiring Harness For 1978-1990 GM Vehicles With 12-Pin Factory Radio • 12 Pin Plugs Into OEM Radio • Power/4 Speaker • Can Be Used To Repair Damaged Harness

www.sonicelectronix.com

 

[CBR600RRider]

where does that harness plug into? Is that way back by the fuse box?

 

[oldeerslayer]

The repair harness has to be connected to each of the cut wires. More than likely has the correct matching colors.
Time for a bit of soldering and shrink wrapping. But it'll get you back to how it was before Edward Scissorhands got in there.

 

[CBR600RRider]

oh, My illiterate *** read that wrong 🤣 and was thinking it was reversed from how you were talking. I'll check the reverse wiring harness out. Definitely would be nice to only have to touch stock wiring.

do you know if the Cigarette lighter works off of the radio fuse?

 

[oldeerslayer]

It does not. IIRC it's on the courtesy fuse.