Headlight Question

[Bruzilla]

My headlights are flaking out on me. I have low beams until I hit the high beam switch and then I have no beams. I am running my lights off relays, so I suspect the relay for the high beams is DOA, but I was wondering if the high beam switch changes the power flow from a low beam circuit for just the low beams to a high beam circuit that provides power to high and low beams?

 

[Glenwood]

If you still use the foot switch, I believe they channel power from one source (headlight switch) to either the low beam or both low & high. That's where I'd start testing.

 

[747mopar]

I'd start right at the relay, usually people mount them where they're easy to get to and the input that triggers them should come directly from the dimmer switch anyways.

 

[Sixpactogo]

If the dimmer switch on the floor has a bad connection or fails to switch internally it will do exactly what you are experiencing so i vote for that to be the problem.

 

[747mopar]

85 and 86 are what triggers the relay, one should be grounded and the other should come from the dimmer switch... find which is grounded then test for 12V while somebody works the switch on the other terminal.

87 and 30 are the switch that turns the light on, one should be powered from the battery and the other goes to the headlight. Very easy to narrow it down right here at the relay.

 

[Bruzilla]

Some more info... I've had this mod in the car for a couple of years now and with no problems, so whatever has happened is a component failure. I'm just wondering if the issue is a relay failure or a switch failure. One relay triggers with the switch in one position and the other when it is in another, but I didn't know if the high-beam relay feeds power to high and low when the switch is set to high beam mode and the switch cuts power to the low beams at that point.

 

[Glenwood]

it's easy to test, just find which is the input (usually +) on the relay and jump it to the battery. if the relay works the high beam will come on. That means it is not getting the signal from the switch, likely the foot switch.

 

[Tori]

Sounds like the problem i had with my car (although without the relays involved) Bad ground where the harness daisy chains the grounds along the core support.

 

[747mopar]

Some more info... I've had this mod in the car for a couple of years now and with no problems, so whatever has happened is a component failure. I'm just wondering if the issue is a relay failure or a switch failure. One relay triggers with the switch in one position and the other when it is in another, but I didn't know if the high-beam relay feeds power to high and low when the switch is set to high beam mode and the switch cuts power to the low beams at that point.

I'm not up to snuff on the 71 and later cars yet so can't help you on whether they're together or not. Doing as Glenwood suggested is where I'd start.

Find out which is grounded out of relay terminal 85 or 86, put 12V to the one opposite of ground... If they come on it's your switch. If not find out which out of 87 or 30 is the supplied 12V and jump 12V to the opposite... If that does it then it's the relay.

Keep in mind with relays added they are now "the" switch that turns the lights on and off, your headlight and dimmer switch only activate them and are in no way controlling the lights themselves.

 

[beanhead]

Just my opinion but I would suspect the relay first...the heat under there wreaks havoc on everything, the footswitch is a mechanically actuated set of contacts I would think if it still clicks and moves normally it's not the problem..

 

[Glenwood]

These foot switches are prone to corrosion inside them and the contacts don't always travel fully nor make good contact. Testing will narrow it down whatever the issue is.