Electrical gremlins -- 72

[techweenie]

Getting frustrated with this.

1. Left headlight is coming on about a second after the right. Same wiring and relay. Moving wires can cause light to go off, but all attachment points appear good. Headlight sometimes goes off while driving.

2. Directional indicators blink at 2X speed, but all the bulbs are working. Both arrows flash in gauge, which usually means grounding problems, but grounding all appears okay.

3. Want to wire in TTG lights. Car had a foglight switch, but I don't have the right colored wires coming from the harness to allow me to use it. Accessing the back of the switch is a Big Deal with the ventilation system in place...

4. (I think this is the easiest) Wired in electronic speedometer, and it works fine during the day. When I turn the headlights on, speedo drops to 0. If I turn the dash light dimmer, the speedometer responds to the rheostat position(!)

I've searched this forum and not seen these issues before. There are some guys who really know the wiring on these cars, but I didn't see any local to me. Anyone have any ideas?

[Gogar]

#2: Make sure you check not only the brown grounds on all four corners, but also check the bulb sockets: turn on the signal and go directly to the bulbs and wiggle the bulb in its housing if it's not working.

[docrodg]

Originally Posted by techweenie

Getting frustrated with this.

1. Left headlight is coming on about a second after the right. Same wiring and relay. Moving wires can cause light to go off, but all attachment points appear good. Headlight sometimes goes off while driving.

2. Directional indicators blink at 2X speed, but all the bulbs are working. Both arrows flash in gauge, which usually means grounding problems, but grounding all appears okay.

3. Want to wire in TTG lights. Car had a foglight switch, but I don't have the right colored wires coming from the harness to allow me to use it. Accessing the back of the switch is a Big Deal with the ventilation system in place...

4. (I think this is the easiest) Wired in electronic speedometer, and it works fine during the day. When I turn the headlights on, speedo drops to 0. If I turn the dash light dimmer, the speedometer responds to the rheostat position(!)

I've searched this forum and not seen these issues before. There are some guys who really know the wiring on these cars, but I didn't see any local to me. Anyone have any ideas?

#1: Check the terminal connections to the wires for good noncorroded connection and same with headlight bulb.

#2: See #1

#3: color does not matter, gage of wire does. Trace to a convenient point for tie-in.

#4: Sounds like you got it wired in line with the dimmer wrong. recheck the install wiring.

[Gogar]

4. Seems like you might have used the Black/Blue wire for power to your speedo; you might check the Red/Black that goes to the tach and see if it is +12V switched with the key.

[RShepHorse]

I've just noted that I've got problem #4 as well in an '84 targa, stock tachometer which works fine during the day, fine with parking lights on. Also, when the speedometer dies [with headlights on], the illumination in that gauge also goes out...

[techweenie]

Gogar, all the turnsignal bulbs are working.

I have a solid red wire to + on the speedo. No stripes. Obviously it is somehow variable via the gauge light dimmer, but there are no other solid red wires. I'm going to pull the steering wheel, turnsignal switch & all gauges & do some wire tracing.

docrodg: car is corrosion-free and all connectors have been on & off multiple times. On the TTG lights, I want to use the switch that should be wired into the harness, but can't find a diagram indicating the colors. Issue is power source wire, not distribution wires (which work fine).