H4 wiring issues

Skiddy · Feb 11, 2017

I have Toms H4 headlight kit (harness, relay's). my stock 74 wires have been hacked some. I have two wires coming in to the head light one green, one red and ran brown to ground. I think I hooked them up like the original headlights were, except the two reds for the hot in the new harness.
here is the issue. I have bright or dim lights not sure which as not sure the bright indicator light is even working.
before changing the head lights, the bright and dim worked. just had the dreaded flicker once in a while. I have a new dimmer switch to put in, not even sure that is the problem though.

B RON CO · Feb 12, 2017

Hi, the standard headlight plug works like this, looking at the back of the headlamp: top pin is low beam, right pin is high beam, and left pin is ground. Use your test light to see what is hot. If both top pins are hot, that is low beam. If both right side pins are hot, that is high. If the indicator lamp in the speedometer is not working that is another thing to get to. I have removed the speedo cable, removed the 4 screws, and twisted the whole thing down to work on the back. Good luck

Viperwolf1 · Feb 12, 2017

Skiddy said:
I have Toms H4 headlight kit (harness, relay's). my stock 74 wires have been hacked some. I have two wires coming in to the head light one green, one red and ran brown to ground. I think I hooked them up like the original headlights were, except the two reds for the hot in the new harness.
here is the issue. I have bright or dim lights not sure which as not sure the bright indicator light is even working.
before changing the head lights, the bright and dim worked. just had the dreaded flicker once in a while. I have a new dimmer switch to put in, not even sure that is the problem though.

Red is low beam, green is high beam. Black is ground.

Skiddy · Feb 12, 2017

sweet, thanks guys, I should add when I hit the dimmer switch the headlights go off. like going to ground. before I put them in, I had I think around 10v to green and around 8v to red.

B RON CO · Feb 12, 2017

Hi, the dimmer switch has 3 wires. One hot from the headlight switch, the other s feed
the high or low beams. Check it with your test light. Good luck

Viperwolf1 · Feb 12, 2017

Skiddy said:
sweet, thanks guys, I should add when I hit the dimmer switch the headlights go off. like going to ground. before I put them in, I had I think around 10v to green and around 8v to red.

Sounds like a bad dimmer switch.

Skiddy · Feb 12, 2017

thank you every one,

I had the green and black backwards. still have to look into the high beam indicator light. now onto the next problem.
since I replaced my fuel line, guess the tranny lines got jealous, stupid azz cheap rubber lines.

well I hope that is where the tranny fluid is spraying out%)

Gwunited2 · Jun 30, 2017

Skiddy said:
thank you every one, I had the green and black backwards. still have to look into the high beam indicator light. now onto the next problem.
since I replaced my fuel line, guess the tranny lines got jealous, stupid azz cheap rubber lines. well I hope that is where the tranny fluid is spraying out%)

Maybe you could help me with my problem since you fixed yours. For the past two years, I have had all of my lights working properly. Two days ago, I turned on my lights, everything (side markers, dash included) works except my low beams in both headlamps. When I click my dimmer switch, both high beams come on. The only lights that don't work are both low beams. Any ideas?

Also, I just buttoned up my leaky transmission. I might be able to help you with that if you haven't already figured it out. Do you have any idea where it's spraying out?

Thanks,

Massey

DirtDonk · Jun 30, 2017

Hey Massey. Sounds like you might have the usual bad dimmer switch, but it could be other things as well.
It's not completely unheard of for both low-beams to go out at near the same time. Even at the same time, although that's pretty rare unless there was a surge.

You could pull the plug on the dimmer switch and run a jump wire between the power feed from the headlight switch to one, then the other wire in the connector. If you get low-beams with the jumper, your dimmer switch is toast.
If you don't, then either the wires, or the lamps are bad.

Might be other things as well of course, but that's where I'd start. The fact that the high-beams work is a good indicator that the main switch, the wire from there to the dimmer are still good. It's only at or after the dimmer that things go wonky on you.

Good luck.

Paul

Skiddy · Jun 30, 2017

yep what Paul said
tranny pressure hose had a hole in it
no more bronco leaks anywhere anymore

until the next wheeling trip%)

Gwunited2 · Jun 30, 2017

Skiddy said:
yep what Paul said

tranny pressure hose had a hole in it

no more bronco leaks anywhere anymore until the next wheeling trip%)

Good to hear.

Gwunited2 · Jun 30, 2017

DirtDonk said:
Hey Massey. Sounds like you might have the usual bad dimmer switch, but it could be other things as well.
It's not completely unheard of for both low-beams to go out at near the same time. Even at the same time, although that's pretty rare unless there was a surge.

You could pull the plug on the dimmer switch and run a jump wire between the power feed from the headlight switch to one, then the other wire in the connector. If you get low-beams with the jumper, your dimmer switch is toast.
If you don't, then either the wires, or the lamps are bad.

Might be other things as well of course, but that's where I'd start. The fact that the high-beams work is a good indicator that the main switch, the wire from there to the dimmer are still good. It's only at or after the dimmer that things go wonky on you.

Good luck.

Paul

Thanks for the quick response. I got the lights working again. One of the red wires (h4 wiring harness) that connect directly to the battery was corroded and broken. I cleaned the battery post, cut the wires and installed a new connector. Everything works properly again. Thanks again for all the help. Nothing but good people and great advice from the members.

Skiddy · Jun 30, 2017

Gwunited2 said:
Thanks for the quick response. I got the lights working again. One of the red wires (h4 wiring harness) that connect directly to the battery was corroded and broken. I cleaned the battery post, cut the wires and installed a new connector. Everything works properly again. Thanks again for all the help. Nothing but good people and great advice from the members.

sweet glad you figured it out,

wiring can be a real pain trying to figure out what some po's have done

Rustytruck · Jul 1, 2017

Skiddy said:
yep what Paul said
tranny pressure hose had a hole in it
no more bronco leaks anywhere anymore until the next wheeling trip%)

Be careful with that. As soon a the fluid leaks are stopped the rust starts.

DirtDonk · Jul 1, 2017

Hah! Ain't that the truth.
Ford should have designed in some more leaks so it would have been protected more from the factory. As it is, we had to wait 40 years for the chemistry and the time to coincide with the money to replace the rust with steel and then coat it against future swiss cheese-a-ggedon.

Of course, that would have been an excuse for brake fluid to leak instead of oil. But hey, at least the missing paint would have been replaced by bare metal instead of rust!

Paul

H4 wiring issues

Skiddy

Bronco Guru

B RON CO

Bronco Guru

Viperwolf1

electron whisperer

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