Wiring.....

I hate wiring!! I am back from my trip and starting in on the wiring in the mav. Most of it is done but I cant figure out why my headlights will not work. I tested the switch and there is power going in and out when I turn them on but nothing gets to the headlights or tailights. I thought maybe because it is a 77 Mav and I am using a 76 wiring harness under the dash and engine compartment. Everything else works but the lights. Any suggestions? Does anyone have a wiring diagram that covers the lighting system? Any help would be appreciated.

JP

 

Do your grill lamps and side markers work?

 

Nope. No lights seem to work.

 

Forgot to ask about the horn, too. That could give a hint.

The head lights, runnning lights (tail, side, front), and brake lights are all on different circuits. About the only thing they have in common is the switch. Feeding power to the switch is a heavy gauge wire, I think mine is yellow, that gets it's power from the fusible link at the battery. Inside the switch is two circuit breakers, one for head lights and one for running lights and horn. Power for the lights at the front of the car go through the firewall connector, power for the lights at the rear go straight back from the switch. I would suspect either the switch is bad, the connector that plugs on to the back of it, or the fusible link up front. Hope this helps.

 

Nope the horn doesnt work either. I tested the big yellow wire and it has power to the switch. When I pulled the switch on, power going out to the lights from the switch was hot like it should be. Not getting to any of the lights or horn though.....????

 

Check for voltage at the lights. One side should be battery volts and the other sid should be o volts. If you have that and the light doesn't come on it is burnt out.
If you have battery volts on both sides of the light then you have no ground to them.
if you have 0 volts at both sides then you need to find the broken connection (open) in your circuit.

PaulS

 

There is voltage to the switch and out of it but I cant find a break. My best guess now, is somewhere in the wiring harness under the dash or something is not compatable between the wiring harnesses. It is driving me nuts...oh well.

 

j.p.thanks,
i now have no headlights.(high or low) . all the other lights work. the horn also works.
...frank...

 

talked to my brother today. he thinks it is the headlight switch. said he sold one at work for a 68' ford truck. said the guy had the same problem i have. will let you know if that takes care of it.

i am in n.c. on vacation so it will be a day or two ...frank...:bananaman :bananaman

 

Frank; wondered where you got to. Forgot you were gone. See you when your return. Be carefull!!!!!

 

got home from vacation, got a new switch and put it in. still no lights . after more checking i found a bad dimmer switch . that was the problem. off and running again ...frank...:bananaman :bananaman

 

Frank; good to hear. Are you off this weekend, and the holiday? I need to come get some mirrors from Mike, and thought we might get together. BTW, there is a classic car parade in Griffin on Sunday, at 2:00pm, and everyone is welcome. Iterested? It will be on TV, so we might get our cars on film. Talk to you later,

 

Hmmm...my dimmer switch is not hooked up. Could that cause a problem?? I tried a couple of other headlight switches...didnt help.

I havent given up yet!!!

 

I can see how that would affect the headlights, wouldn't think the other lights would care. Let us know, maybe we'll all learn something.

 

the power for the head lites loops through the dimmer switch. one side has two wires, one to the brites/ one to the high beam indicator lite.the other side goes to the low beam lites. the center one is the power. ...frank...:bananaman :bananaman