Weird lighting and wiring issues Silvia front end & interior

[Cgeigert]

Been straightening out some wiring issues done by the previous owner. Finally got all the excess wiring removed and fixed a couple issues. I had a burnt out part in that relay control box so I jumped it with some wire and that brought back the interior lights. Now all the gauge and other lights work fine except for the illumination lights in the controls around the steering wheel. Another weird issue is with the lights in the Silvia front end. I wired them up a while back and they have worked fine. I hooked up the yellow fogs using the signal from the bumper lights. Now when I step on my brake the fogs light up. I can't think of how the brakes could have possibly gotten mixed up with any lights from the front. Anybody heard of this?

[Hijacker]

Something else is afoul. The brake lights and marker lights are two isolated circuits. You could have some rubbed wires in the harness causing the two circuits to jump. So when you push on your brakes, the marker lights are lit up. I had a similar issue with my brake and reverse lights. The harness had rubbed against the scissor jack and rubbed through the wire sheathing.

As for the illumination lights on your dash, check the lighting adjuster switch (the one that changes the intensity of the lights). All of the lights on the dash controls ground out through that. However, I would assume the gauges wouldn't light up either since those are on the same circuit. It could just be a case of all the lights being burnt out. The bulbs in the switches are pretty notorious for dying, and at this point are really really old.

[Cgeigert]

I looked into it tonight and it's actually the fogs, and the bumper lights which are connected plus the gauge lights. So at least 3 different light circuits linked together somehow. Could it be that timing control relay or whatever? I checked over most of the wiring in the car and it looks ok. Only other thing I can think of is I ripped off some of the harness in the wheel well last weekend during an autocross. It was just the part with the connectors for the windshield washer reservoir so shouldn't affect that. I was bottoming out a couple times so now that I think about it I'll check under the fenders and see if I rubbed something. Where on the car harness are these 3 things running next to each other?

[Hijacker]

The brake light circuit doesn't go to the main harness around the nose of the car. After the fuse box, it runs to the pedal switch, then to the tail lights, then grounds out. If there's any form of rubbed wires crossing, it would happen anywhere in between there.

Now, your gauge lights and bumper lights are all on the same circuit. The only difference is that the bumper lights ground out immediately. The gauge lights return to the dimmer switch, and then ground out.

Double check the main harness for any rubbing to see if there are exposed wires. The other thing I would look at is any place you've spliced wires in the car. If you want the fogs to run with the bumper lights, they should have been tapped into the Red/Blue wires running to your bumper lights. I tend to dislike this method particularly because the circuit isn't designed to supply the circuit with enough current to run H3c bulbs. It could lead to a premature switch burnout. When I was wiring mine up, I used the pop up switch to supply power off the marker light circuit (R/L) and always noticed the lights dim substantially when the fogs were turned on. Moving the fogs to a dedicated circuit was the best move I made.

All preaching aside, you have rubbing wires somewhere in there.

[Cgeigert]

Thanks for the info. Currently they are wired up the easy way but I plan to do the other method you did. They've worked fine for almost a year up until now. Only other new thing I did was wire up boost gauge to green wire coming from headlight switch so it turns on with lights. Also replaced auto seatbelts with s14 ones. I still can't think of where the two circuits would come in contact, they seem to be be on totally separate paths. I'll check it out more today I guess.

[Cgeigert]

Checked some stuff out again. All the wiring looks good. I was looking at FSM and the only place all three come in contact is by driver side fuse panel. Instrument lights go up to dash from there. Brake lights go back along driver side door fender. Bumper lights/fogs go through firewall into fender to front. I really don't see how all of a sudden wiring there would suddenly go bad, it has to be related to something else. Pulled out control relay box and nothing changed. Pulled brake light fuse and all three stayed off. Could it be related to a ground? Wouldn't think so.

[Cgeigert]

It was the effing LED's!!!!!!!!!!! I had been going over all the wiring in the car and the wiring diagram and everything looked good. I has done a bunch of different things to the car so I was thinking back to what I had done. For years I've been using Catz LED bulbs with no problems. One of them had gone out recently so I replaced all 4 of the 1157 with some cheap LED I had lying around. The bulbs were somehow making the other lights go off when I hit the brakes!!!!!!!!!!!!