Headlight Electrical Gremlins

[Ransom_nf]

So I’ve learned lots from this forum. Up until now just reading what’s been posted has been answering all my questions.

Until now...

I have swapped my dimmer switch, changed the plug. As shortly after I bought the rig it I noticed the smell of burning wires. And of course it was this troublesome switch.

Well now I have the relay set up from Bronco graveyard and am blowing headlights. So I tried out a set of leds i had I didn’t want to install. The leds stay on at all times.


When truck is off... everything seems to work perfect.
Lights off when switch is off.
Running lights on when switch in middle.
And high beams when you turn high beams on.

When truck is turned on this is when things get special....

When switch is off. High beams on. When switch is on low or high depending on the selection.
But permantly lit up....

What in the name of god have I got done?

Also after removing the bronco graveyard relay set up I noticed. Plugging the led lights in and turning the dimmer would give me some flicker on the led when lights were in off position.


I’m stumped. I’m hoping one of you can help.

 

[Thewespaul]

Start with pulling the connector off the back of the headlight and measuring voltage at the plug, pull the relay out and test to see if it’s stuck shut with a continuity test.

 

[retiredinhomer]

So I’ve learned lots from this forum. Up until now just reading what’s been posted has been answering all my questions.

Until now...

I have swapped my dimmer switch, changed the plug. As shortly after I bought the rig it I noticed the smell of burning wires. And of course it was this troublesome switch.

Well now I have the relay set up from Bronco graveyard and am blowing headlights. So I tried out a set of leds i had I didn’t want to install. The leds stay on at all times.


When truck is off... everything seems to work perfect.
Lights off when switch is off.
Running lights on when switch in middle.
And high beams when you turn high beams on.

When truck is turned on this is when things get special....

When switch is off. High beams on. When switch is on low or high depending on the selection.
But permantly lit up....
check the dimmer switch plug you replaced I think you crossed a wire.

What in the name of god have I got done?

Also after removing the bronco graveyard relay set up I noticed. Plugging the led lights in and turning the dimmer would give me some flicker on the led when lights were in off position.


I’m stumped. I’m hoping one of you can help.

 

[Ransom_nf]

When I installed the plug I soldered the connections one by one. Double checked the colour coding today it looks good.

I pondered this today when I swapped the switch AGAIN thinking it might be a bad replacement switch. I also swapped out the foot switch today thinking that could be the issue.

I’m wondering if the simplest solution might not be to just run 2 new wires from the switch to the relay Install a new 9004 plug head on these 2 wires and see if bypassing the old girls wiring harness sorts the problem. It strikes me as weird that everything works fine when the truck is off and freaks out when the truck turns on.

I assume knowing how hot that switch can get that wires might have melted and created a short.

When I check plug with the Multimeter. When in high should it only be the high circuit that is powered or does the low beam circuit stay powered at the same time?

 

[snicklas]

I’d still bet you have a grounding issue. If it works when the truck is off,it can use any wire to “find” a ground, even if it’s something’s “hot” wire. So no current flow, and the circuit can backfeed to a ground. Then the power on in the wire that it’s using as a ground, now what was finding a ground the wrong way, now has current flowing “blocking” the path to ground. Now it has to try and use its correct, bad ground, and then funky things happen.

This is like the vehicle that has a bad ground in the taillights, and when the brake is applied, instead of the brake lights coming on nice and bright, they are dim and the backup lights come on. The brake light circuit is “finding” a ground through the backup light circuit.

 

[Ransom_nf]

Well then job one today is to clean up my grounds. Seems strange that there is still an issue after installing the bronco graveyard harness with relays? It has its own grounds?

 

[Ransom_nf]

I’m going to get 2 new 9004 plug ends today as well to swap those over. What about putting a new ground at each of the plugs. Is that a good idea or should I really start snooping through all the ground locations.

 

[chillman88]

So when exactly did the issue start? When you changed the pigtail for the switch? I'm with Wes on this. Yes grounds are good to check but check the new harness first and make sure power is where it should be. Then I'd plug the switch in and do the same test from the back of the plug checking each position on the switch. After that I'd check the grounds near the headlights and then try to trace the harness and find a possible melted wire.

The relay kit is great but they don't take much juice, so you might have had a problem before that you didn't know about until you put the relays in.