No headlights?

[snatiep]

Hello Everyone,

This morning I noticed my headlights were not working, neither the low beams or the high beams.

The side marker lights, turn signals, brake lights, all work fine. It's just the low and high beam headlights that aren't.

I took off the fuse cover from the left side of the dash inside the cab and all of the headlight fuses are good.

I opened the fuse box in the engine compartment and the one headlight fuse is also good.

I used a meter to check all fuses.

I also have 12v power at all of the headlight fuse sockets, both inside the cab fusebox and in the engine compartment when I have the main headlight switch turned on.

I removed both headlight bulbs and there is not 12v power at either.

Do you think it could be the multifunction (turn signal) switch?

A few times in the past couple of weeks when I would turn on the right hand turn signal, it would click really fast until I cancelled the signal and re-apply it then it would be fine. Also sometimes when I would push in on the windshield washer button it wouldn't work unless I pushed in pretty hard on it.

I'm at a loss of where to check next and would be very grateful for your help?

 

[adsm08]

The MFS may be at fault. It can be component tested with a multi-meter by checking resistance between the pins for the headlight circuits.

 

[snatiep]

Thanks for your quick response!

You don't happen to have a diagram showing what pins are used for the headlights on the MPS do ya? Or a link how to test it?

I'm thinking I might take a drive to the salvage yard tomorrow morning and get one to see if that fixes it. I hate just throwing parts at something hoping that will fix it though.

 

[adsm08]

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[snatiep]

Well shoot, I went to the salvage yard and picked up both a mfs and headlamp switch and neither of them solved the problem.

What step should I take next?

Are there any pictures or diagrams that show what path the headlight bundles take back to the fuse box? Or do I just have to start unwrapping the tape from them and unravel them?

Once again I thank you for your help.

 

[martin]

shooting in the dark here, but if your truck has daytime running lights, a bad module can cause weird issues.

 

[snatiep]

nope, no daytime running lights.

Is there a way I can check for continuity between the headlamp sockets and either of the fuse boxes or switches?

I'm dreading having to start opening up the wiring bundles to hunt down the problem.

 

[Andy D]

YUP pull the head light fuses and use an ohm meter or a continuity tester on the wires at the socket