Electrical Gurus needed!

SmokeyVette

SmokeyVette

Adrenaline Junkie
Joined
Mar 24, 2008
Messages
205
Location
Leveldirt TX (Levelland)
I'm having a problem with my headlights.

First, the dims quit working, I thought it was the broken dimmer switch but it turns out that it wasn't. I've been driving around with brights only (I re-aimed them so they wouldn't be as bad) when I NEEDED to drive her at night, but now the brights have quit working as well.

All bulbs are good. The headlight switch is old so I bought a new one, same problems with new one installed. The parking lamps and tail lights work when the switch is pulled out but neither the dim headlights nor the brights will work.

Wrap your heads around this, the other night, before I lost them completely I turned on the headlights and nothing happened for about 30 seconds, and then they came on and worked all night.

To me, this looks like a stuck/bad relay, but I can't find a relay ANYWHERE in the headlight circuitry.

Have any of you had any problems like this before? What do you think it could be?

I swear to all that is holy, if there's a headlight relay in the console or by the heater core I'm gonna blow a gasket!:sos::suicide::club:
 
If the headlight switch is good,the dimmer is good and the bulbs are good that leaves the connectors the bulkhead and ground.
edit-no relay from factory
 
DWncchs said:
If the headlight switch is good,the dimmer is good and the bulbs are good that leaves the connectors the bulkhead and ground.
edit-no relay from factory
Click to expand...

Yep...turn the headlights on and wiggle each connector on the dimmer switch, headlamp switch and harness bulkhead. May be time to replace the lamp harness.
 
You've replaced the headlight switch and everything works but the headlights. There are grounds for the headlights in the front at the center of the hood between the horns, and then the core support to the frame. Look at your diagram and find the ground wires from the headlight bulbs to the frame. Like DWncchs pointed out- it's going to be a ground someplace.
 
I swear to all that is holy, if there's a headlight relay in the console or by the heater core I'm gonna blow a gasket!

It's buried behind the center defrost vent up against the firewall/wiper galley....




















just kidding.....no such thing exists, and the guys above have nailed it....:hissyfit::lol:
 
Ok, there is one ground up front that I know of that isn't connected, BUT it hasn't been connected even when the headlights worked. I scraped the radiator core support to bare shiny metal and touched the ground to that with the switch on and got nothing. God I hope it's not a burned up power wire, I found a nick in the insulation of a power wire going to the headlights and a burn spot where there has been some arcing. I'm going to double check the fuse box tomorrow, then trace out all grounds, then get to rewiring if I have to...

Thanks for the help folks!
 
TimAT said:
that was cold Gene, just plain cold,:rofl::club::mobeer:
Click to expand...

It's a reaction to my goof, I failed to tighten the end bolts on the upper control arms rubber bushings I just installed ....and to boot aligned the front end...

and I don't wanna admit how I found out today about the loose bolts...nothing super bad....

:surrender::push::twitch::eek:
 
More than likely the dimmer switch and on a 77 it is pretty easy to convert to an older style foot dimmer if you don't want to fuss with the column.
 
Didn't see that above.
Unplug the connector to it and you can test and jumper the high and low headlights from there to test.
 
This is why you ditch the stock setup and go to a relay powered setup straight from the alternator
 
Well, the wind decided to blow today, we had a mild cold-front roll through, so I just said screw it, and I ran new wires from the dimmer switch to the headlamps. The lights work! I have an open somewhere between the dimmer and the lamps but I couldn't tell you where.

Now, I'm on to my other wiring problem.

The blinkers don't flash on either side. The hazards work, there is only one flasher unit, and all bulbs are good.

What say ye on this?:suicide:
 
There are 2 flashers, one for blinkers one for hazards. The one for the hazards is not on the fuse box, it's dangling somewhere near the steering column. Originally it's taped to the main harness that runs above the steering column.
 
Twin_Turbo said:
There are 2 flashers, one for blinkers one for hazards. The one for the hazards is not on the fuse box, it's dangling somewhere near the steering column. Originally it's taped to the main harness that runs above the steering column.
Click to expand...

On my '72 the turn sign flasher was dangling off the strut on the PASS SIDE near the a/c vent...beleive it or not, and supposed to have been a stock location, the 4 way plugged into the fuse block top/left corner.....

I think the bulkhead connector needs be taken apart, and reconnected, there are two sections to it, that sorta mate together, one is the main harness to engine/alt/starter/battery/whatever.....the other smaller section is dedicated to the front lighting harness....and somehow that install is messed up....

long long time ago in a land far far away, I fought that war.....:smash::surrender:
 
Ok, I've only noticed one bolt that holds it together, are there more? I'll take it apart, clean it, and put it back together but I don't want to break it and leave myself with only one vehicle especially now that my wife will be having knee surgery tomorrow and she'll have to take the Nova. I don't really want to drive her Ford so that leaves me the 'vette.:lol:
 
Engine side there is ONE centered bolt I forget 5/16 or 3/8 cap, that loosens the plug from the plastic on the backside of the fuse block...

fuse block is held by two bolts diagonally across from each other....from inside 5/16 I think....:smash:
 
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