suddenly no low beams

[laserfish]

Have H4 halogen and either Toms or Wild Horses heavy duty wiring harness, don't remember. Suddenly have no low beams. High beams, running lights, side marker lights, turn signals and brake lights work fine. Switched the relays, same problem. New high beam switch. No voltage at the white wire in the headlight plug. Plugged in the old harness plug and both low and high beams work (much dimmer). What would cause this. I would think if it was a relay, switching them would cause the problem to reverse.
What could cause this? Where do I start? Need to get this fixed so I can get it inspected and on the road again.

 

[BGBronco]

not the same lights, but when I went through this, both of my low beams were burned out. I spent way too much time looking for complicated problems before realized it was an easy one.

 

[Slowleak]

I think the Toms harness has a fuse in the wire between the battery, or power source, and the relay. Have you checked for fuses?

 

[laserfish]

Low beams do work, not burned out. Was hoping that was it. Will look for the fuse, but high beams do work, so I dont think it would be a fuse unless they are fused separately.

 

[B RON CO]

Hi, I would use a test light and see where you lose the current. At the dimmer switch, there are 3 wires, one from the headlight switch, and one to the high beams ( which should be working) and the other to the low beams. So check out what happens from the dimmer switch to the relay.
As mentioned, both bulbs could be burned out, and you could check the headlight plug with your test light.
My night lighter head light harness did not come with fuses, but I added them to protect the circuit.
Good luck

 

[Slowleak]

Low beams do work, not burned out. Was hoping that was it. Will look for the fuse, but high beams do work, so I dont think it would be a fuse unless they are fused separately.

I just checked mine. They are fused separately.

 

[laserfish]

Slowleak, you are the winner. Bad fuse. Now, where do I find that odd fuse. I guess i could just splice in a normal fuse. Suggestions?

 

[Slowleak]

Slowleak, you are the winner. Bad fuse. Now, where do I find that odd fuse. I guess i could just splice in a normal fuse. Suggestions?

Woohoo.... mine uses a standard two blade auto fuse. Take it to a parts store. If it is something really odd, you might want to replace it with a standard fuse.

 

[laserfish]

Yep, replaced with an ATO that matches all the others.