guitarman376

So I have some questions on my headlights. Awhile back, they were dimming low then going back to normal brightness. I replaced my voltage regular, and the problem went away. Then the motor was rebuilt, so the regulator/car wasn't being used. Once my car got back on the road, I noticed that now the headlights are going from normal to really really bright, but only during speeds 40+ mph.
When they go bright, its so strong that I'm worried people think I'm flashing my high beams at them. In fact, I didn't even think they could get that bright because as long as the car has been in my family they have always been sub-adequate in terms of brightness. I can imagine 4 possible problems:
1) voltage regulator was bad and/or fried
2) I have read that headlight switches go bad...maybe that's it?
3) old headlight wiring harness? not too sure about this
4) the alternator didn't get replaced...coincidence or culprit?

My lights are stock, not upgraded or anything. I have a basic stereo and my alternator puts out enough amps to cover everything. However, the alternator is NOT new by any means. What things should I look out for? The wiring harness didn't have any obvious signs of issues, but I know finding problems with wiring is like finding snakes in grass.

LynnBob Mustang

A loose or bad ground wire???

Lynn

guitarman376

Where would the ground be? I recently replaced all the battery cables and cleaned the attachment points.

jlg2002

It is possible that it is the headlight switch or dimmer switch. First though, you need to get a voltmeter on the battery and look at what the voltage is at around 3000 rpm with the headlights on and off. If its all over the place it may also be the V reg.

guitarman376

jlg2002: you are making me think it is the headlight switch, because come to think of it one of my dash bulbs burnt out recently...definitely going to order a new switch... I'll do that voltage test and update results.

guitarman376

Without lights on I got a reading of 14.2 volts and with them on I got 13.6

jlg2002

those numbers look adequate so I'd look at a new HL switch first also.

fastbackford351

Inspect your grounds then replace your headlight switch and be done with it.

Get a good one.

guitarman376

Ok, so I'm assuming that a switch from any of the main suppliers we all use will be cool. Once schools out I will do this and post results. Thanks to all.

fastbackford351

The stuff you buy at Autostoned or the like will more than likely be Chicom crap. Maybe check Ebay for an NOS unit. I bought one for 50-60 bucks but I figured it was worth it after I replaced crappy headlight switch after crappy headlight switch, (about 3 in 2 years) until I went NOS and it's been over 5 years with nary a flicker.

One and done.