This thing is driving me nuts, here's whats wrong:

1. Headlights are very dim, even thehighbeams are barely enough to drive at night.
2. When the headlights are on, the turn signals, brake lights, and taillights do not work.
3. There is an oddtapping/rubbingnoise coming from therear of the car when the lights are on. (Does this even with all accessories/engine off)
4. Instrument lights don't work.

Any idea if these are all related? I've been staring at the wiring diagramall dayand can't see what could possibly cause this!

 

Mine work, but not very well. It sounds like you have a problem somewhere, possibly a short. You are definitely getting a voltage drop in the lighting circuit. What is the voltage at the headlights?

I have recently ordered a headlight kit from reenmachine. There is also a do it yourself kit in the FAQ section. You may try that to see if it helps. It bypasses the stock wiring so it will supply full voltage to your headlights wichout sending that current through the stock switch. Relays are great things!

 

Swap out your headlight switch and see what happens.

 

Check the alternator voltage too.

 

1st question: What kind of shape is the wiring in? Is it nice and neat or has it been hacked and cobbled together? This adds greatly to the complexity of the trouble shooting.

If it is nice and tight then I'd be willing to bet a head-light switch swap would do the trick. I had very similar symptoms in my '65. 40 year old switch was going south.

 

+1 on the switch...that fixed ours, but you need to find out what that noise is in the back of the car...if its a short, you don't want it torching a fine ride!! i would try finding that before the switch...

 

+1 on finding that 'tapping/rubbing' sound ASAP. I glanced right over that part of the post.

Is your harness getting hot when the lights are on? Check the tail-light harness for excessive heat when the lights are on.

What does your voltmeter read while the tapping/rubbing sound is taking place?Is it steady? Too high? Too low?

 

First off I would check the noise, that is definately not normal. Once that is fixed, that may fix your problem. If not, then I would check the voltage at the alternator, making sure it is optimal. Next, check you wiring, you may find some brittle/corroded wiring that is barely connected together. You might want to think about the switch too. If you end up replacing any wiring, think about adding a relay to your lights. If this is the original wiring, something over the years could have chewed on the wiring too. Have you ever heard of wire chaffing?

 

yah. find the noise. if that doesn't fix it, measure if you have:
12V+ over battery when car is running
then check if you have around 12V at headlight+ to battery-
if that's ok then check if you have around 12V from headlight+ to headlight ground

let us know which of those is not ok