Fog Lights and Passenger Low Beam not working

[Nutmeg]

Found my fog lights not working along with the low beam on the passenger side. Changed out the headlight bulb still no low beam. Checked the ground wire on the firewall it appears good along with the butt splices for the interface to the builders harness. Looking in the manual the low beams each have a separate fuse so the next step is to snake all 6'4" of me around the drivers seat to check it tomorrow. Before performing that circus act wanted to post if anyone else has had a simular problem and what did you find? Headlights, both high beams work and the drivers low beam. Fog lights, neither work and the switch on the panel does not light either. Manual does not list a fuse location for the fog lights, any idea on how the system is wired? Location / # of feed fuse? If it is a directly switched circuit or a control circuit to a relay. Thanks

[Nutmeg]

So we dove in to tracking it down and this is what we found. If you rotate the driver chair 45 degrees in in makes it easier to get to the fuses. My fuse for the low beams was good and I found that the fuse panel is after the panel light switch so that was good also. Next we disconnected the factory plug under the hood to check for power. The plug showed power so I felt good that the multi-function switch in the dash must be good. Plugged the assembly back together and no light still. Ok must be in the wire from plug to bulb. Start separating the wires and UPS shows up. Go get my package and as I turn around the low beams are on. Arrr. Well they work.

Fog lights I found have a relay that is switched from the high beam output. It gets is feed from a bule wire with trace that heads into the cab by itself. After it stops raining we will return on that. If anyone knows its power source it would be nice, pulled the likely fuses in the box and none were blown.

[cfsoistman]

I had a situation where I had no headlights low or high beam. Found that the ground wasn't contacting the frame. FR had used a self-tapping trim screw and a washer through a very large terminal O-Ring connector. The threads had oxidized and it was no longer in contact with the frame. I removed it, wire wheeled off some paint where the hole was located, drilled out the hole and put a bolt with lockwasher and nut in place of the screw. Sprayed terminal protector on it and it's worked fine since.

[Nutmeg]

Charlie, Following your old post that was the first thing I checked. Most electrical issues I have seen on RV's are from poor grounds not poor power. Now a little foot in mouth but may save someone in the future. The vehicle needs to have the key in the run position for the fog lights to work!! Got off track when you turn the lights on how all the switches except the fog light light up. Second learning point is the relay is not switching power to supply the fog lights, rather it interrupts the power turning them off when the high beams are activated. Ok that ends this weeks lesson on lighting.

[nemo45]

Originally Posted by Nutmeg

Charlie, Following your old post that was the first thing I checked. Most electrical issues I have seen on RV's are from poor grounds not poor power. Now a little foot in mouth but may save someone in the future. The vehicle needs to have the key in the run position for the fog lights to work!! Got off track when you turn the lights on how all the switches except the fog light light up. Second learning point is the relay is not switching power to supply the fog lights, rather it interrupts the power turning them off when the high beams are activated. Ok that ends this weeks lesson on lighting.

Ok, how about a lesson on clearance lights. Mine all work except for the amber ones over the cab. I turned on the ignition switch too, thinking that might be the problem.