I own a 1974 c3 and one night I turned my headlights on in a parking lot without the car running and they suddenly cut off as if a fuse blew. I know there is no headlight fuse in the fuse box and I tested powers and grounds at the lights and got no power. My low beams work just fine though. I also replaced the headlight switch and still nothing.

Someone mentioned somewhere about an inline fuse that may exist somewhere. Can anyone help?
Thanks!

 

check your dimmer switch? should see voltage coming in and out. Under your carpet left side

 

light blue from headlight switch has 12 volts and at dimmer switch tan is low beam and light green is high beam

 

Thanks for the advice, checked and I'm getting power at blue no problem, green when high and tan when low. Nothing out of the ordinary there

 

FWIW - A new dimmer switch is $5 at O'Reilly's and floor mounted dimmer switches are famous for failing because of internal corrosion.

 

Yeah mine allready works though for sure

 

The left side feeds the right side so check for a break at the IN side of the socket.

 

Then if you are getting voltage AT the dimmer switch on the light green wire. The that is telling me that it is doing its job and your high beams should be working

.When you go to high beams, do ALL of the four headlights go out....or just the inner ones?????

Then when you switch it to low beams just the outer bulbs work....correct???

IF all four bulbs go OUT when you go to high beam I would look into your wiring harness that runs down the side of the inner fender skirt and see if when you have the high beams on you are showing current on the light green wire. I check if just behind where you hood prop support is.

IF the outer two bulbs go to high beam and the inner ones do not then I would look a the wiring that goes to those bulbs.

IF you still do not have power at the light green wire at the hood prop support. I start top work my way back towards the firewall junction block adn see if I get power there. IF I don't...then I remove the bulkhead connector CAREFULLY and test the wires by using my ohmmeter to see if all of the wiring form that connector to the headlights is good...and if the light green wire at the dimmer switch is good to the terminal in the junction block still mounted on the firewall on the engine compartment side.

IF you need to take off the firewall wiring junction block it takes 3/8" six point socket. And when you go to start to remove it.. Begin to loosen the bolt and when you being to feel tension and resistance.. STOP an carefully pull back on the harness connector and see if it is beginning to want to come off Then...when you go to loosen the bolt some more you should feel that there is no resistance...because you were successful in getting the wiring black back some...then it will begin to have resistance again when you try to remove the bolt some more.... do that again until you feel a resistance and pull out on it again and again until you get it off.

REASON for this is IF you jump in and try to just unbolt that bolt. What can happen ( and do not ask me how I know this) what can happen is that the special tubular threaded nut that is pressed into your inner fuse panel will actually push out...and when you go to try to put that bolt back in...there is nothing there for the bolt to grab onto due to it fell out and dropped.....thus causing you to have to now drop the inner fuse panel and separate it and reinstall that tubular nut.

Sometimes the black sealant that GM used at the firewall bulkhead can be a bit tough to get it to break that seal...just so you are aware of that.

DUB

 

Thank you guys so much for the help.

I have an aftermarket Wagner stationary headlight kit on the car and it turns out both fixtures we're completely shot. Excess voltage somehow. I'm gonna order LEDs instead since they're brighter and can withstand a light power surge.

thanks again!!

 

OK..NOW I KNOW what the problem is. FACT: The wirng in the connectors that would plug into the FACTORY headlight is not wired correctly for the stationary square headlgiths.

Reason I KNOW this I just had to deal with this SAME EXACT ISSUE several months ago on a Corvette and I called Wagner and they told me what terminal was for what and I had to move the wires in the connector to make it all work.

DUB

 

Yeah I allready ended up rewiring them, actually I did it so only the inside lights come on for highs and outsides come on for lows. I also took a fixture out and used a jump box to give it power and ground and it's definitely shot in my case lol thanks though!

 

So I am assuming that you removed a wire on your outer headlights so ONLY the low beams work??? I do know that the wires in the connector need to be switched around due to the three terminals in the bulb itself are not like the original bulbs are in how they work the bulb.

IF you have the inner bulbs...which are high beam bulbs and have only two terminals on the bulb...and they are not working...then I am suspect that you are getting power to them when you go to high beam.

IF your inner headlights have three terminals on them for some odd reason...then if you are getting power to the light green wire...you may need to get the socket connectors for a three wire headlight and wire it up like Wargner will tell you.

DUB

 

Okay thank you I'll look into it then