Electrical Weirdo wiring problem
mickey85
Jeeper
- Posts
- 21
- Thanks
- 0
- Location
- Valparaiso, IN
- Vehicle(s)
- 83 CJ7, 258, T5, Dana 300, Dana 30 front axle, AMC 20 rear, Trac-Lock LSD
Note that I'm cross-posting this from JeepForum as well...
Okay, so for a bit of backstory, I'm restoring my dad's 83 CJ7 . It still has the original computer controlled carb, still has the original ignition system, and still has mostly the original wiring harness. I had the computer and ignition harness rebuilt, as mice had eaten the wires by the ECM plug. Dad wanted the thing back as stock as possible, but he passed away, and I'm trying to honor his wishes.
I had a no-spark situation, but thought I'd remedied that when I read JeepHammer's stuff about grounding and wiring and such. I spliced a ground wire into the distributor ground wire, and got a great spark. Got the thing to run really well, but I think I may be back to no-spark. That's something to deal with later (by the time I was done today dealing with battery problems, the battery was so tired it didn't want to turn over the motor much, and it didn't make spark. I may have cooked the module, but I have a spare if so).
Here's what I've done so far:
This is the front of the driver's side fender. The purple wire grounds both sides of the headlights and marker lights. The two blues are 12 gauge. One runs to the headlight switch mounting screw (the mount that runs through the dash panel). The other runs to a small stud I have on the firewall to ground dashboard stuff.
Passenger side dedicated ground. 12 ga to battery negative, little black wire (16 ga?) to ignition ground, 12 ga to the alternator case (which is also spliced to the head)
Alternator wiring. light blue is 10ga fusible link to the battery side of the solenoid. Dark blues go from the head, to alternator, to dedicated ground. I replaced the plug, and it seems really tight...
Under dash. Blue 12ga goes to dedicated ground on the DS fender. Black to the left goes to aftermarket tach, black going up grounds a mounting stud for the speedo assembly, black to the right grounds the oil pressure gauge light.
Now, this is what's happening. When I twist the light knob (for the dimmer), the gauges and 4x4 light respond:
And I have no idea. There isn't anything added to the harness under the dashboard, and there shouldn't be any reason why it does this. I'm also getting a clicking on the passenger side of the engine bay when I twist it counterclockwise, but have no idea what it is (I didn't have a helper with me to explore further).
Also, what the hell are these plugs? I can't find them in the wiring diagram, and Dad didn't label them. There's also a two-prong connector by the parking brake that is connected to the dimmer switch wires. Does that go to the parking brake warning light? I don't seem to have that, and can't find a replacement, so I don't know. The yellow/orange ones taped together appear to be for a dash light, but they don't seem to have a home...
Also, where do y'all plug in your tach light?
Okay, so for a bit of backstory, I'm restoring my dad's 83 CJ7 . It still has the original computer controlled carb, still has the original ignition system, and still has mostly the original wiring harness. I had the computer and ignition harness rebuilt, as mice had eaten the wires by the ECM plug. Dad wanted the thing back as stock as possible, but he passed away, and I'm trying to honor his wishes.
I had a no-spark situation, but thought I'd remedied that when I read JeepHammer's stuff about grounding and wiring and such. I spliced a ground wire into the distributor ground wire, and got a great spark. Got the thing to run really well, but I think I may be back to no-spark. That's something to deal with later (by the time I was done today dealing with battery problems, the battery was so tired it didn't want to turn over the motor much, and it didn't make spark. I may have cooked the module, but I have a spare if so).
Here's what I've done so far:
This is the front of the driver's side fender. The purple wire grounds both sides of the headlights and marker lights. The two blues are 12 gauge. One runs to the headlight switch mounting screw (the mount that runs through the dash panel). The other runs to a small stud I have on the firewall to ground dashboard stuff.

Passenger side dedicated ground. 12 ga to battery negative, little black wire (16 ga?) to ignition ground, 12 ga to the alternator case (which is also spliced to the head)

Alternator wiring. light blue is 10ga fusible link to the battery side of the solenoid. Dark blues go from the head, to alternator, to dedicated ground. I replaced the plug, and it seems really tight...

Under dash. Blue 12ga goes to dedicated ground on the DS fender. Black to the left goes to aftermarket tach, black going up grounds a mounting stud for the speedo assembly, black to the right grounds the oil pressure gauge light.

Now, this is what's happening. When I twist the light knob (for the dimmer), the gauges and 4x4 light respond:
And I have no idea. There isn't anything added to the harness under the dashboard, and there shouldn't be any reason why it does this. I'm also getting a clicking on the passenger side of the engine bay when I twist it counterclockwise, but have no idea what it is (I didn't have a helper with me to explore further).
Also, what the hell are these plugs? I can't find them in the wiring diagram, and Dad didn't label them. There's also a two-prong connector by the parking brake that is connected to the dimmer switch wires. Does that go to the parking brake warning light? I don't seem to have that, and can't find a replacement, so I don't know. The yellow/orange ones taped together appear to be for a dash light, but they don't seem to have a home...


Also, where do y'all plug in your tach light?