4 pin Trailer Lighting connector not working

dougranier you nailed it! Thanks. I found 2 fuses that were blown evidently one left one right and that corrected the problem. They ware located in a fuse panel labeled Monaco 2. I will check out my towed to see if I can determine what may cause the fuses to blow.
Again thanks for your help and all the replies from the others!
Chuck

47LS3 wrote:
Thanks again. I have been trying to find the power source(fuse)?For this Roadmaster chassis, Endeavor. None of the fuses,that I have found, are labeled as trailer or tow etc. I suppose I could pull every fuse one at a time looking for a bad one..
I have attempted tracing the yellow and green wires. All wiring is inside the convoluted plastic conduit. There are about 50 bundled together running thru the engine compartment and I gave up.

Chuck

They are rarely labeled. I ALWAYS have the Ignition key ON and then check EVERY fuse at all the chassis fuse block assbly's. I use a 12 volt troublelight and it takes no more than 10 minutes to check all the fuses. This way you find every fuse that is blown even the fuses you did not know were bad. Doug

Thanks again. I have been trying to find the power source(fuse)?For this Roadmaster chassis, Endeavor. None of the fuses,that I have found, are labeled as trailer or tow etc. I suppose I could pull every fuse one at a time looking for a bad one..
I have attempted tracing the yellow and green wires. All wiring is inside the convoluted plastic conduit. There are about 50 bundled together running thru the engine compartment and I gave up.

Chuck

The 7 way and the connected 4 way are fused seperately from the Chassis system. That means the Tow plug will have seperate fuses. They started this almost 20 years ago to prevent a short in the Tow wiring from disabling the RV or Truck lighting. You do not state if Ford/Roadmaster/Freightliner or Workhorse. Endeavor should be a Roadmaster chassis. But they all have separate fuses for the Tow plug. Those fuses will be in a standard fuse block with other chassis fuses. Doug

If the lights on the coach work you have a poor connection, probably corrosion. Trace the yellow (left turn) and green (right turn)from the plug back to their source.

Thanks for the fast reply! I checked the ground, I cleaned a spot on the frame measured resistance from there to the bare pin on the connector and had 0 ohms. With a turn signal on I get no voltage or lights with a test light on any pins on the 4 pin connector. My brake lights are run separately.

Chuck

If nothing is working I would check the ground first. The bare pin on the 4 way on the rig is the ground. All the positive pins are covered in rubber. You can also use a 12 volt test light or volt meter on the covered pins to see if you have voltage. Be sure the test light or meter has a good clean ground bolt or bare metal. One of the covered pins is running lights (usually brown wire) and the other two are left and right signal (usually green and yellow). When the brakes are applied both those wires are hot and when the signal is turned on one of them will then flash.

Try the running lights. If they work then the ground is good.