Tow Vehicle Brake Lights

[Capt Bravo]

When the tow vehicle is hooked up to the motor home, directional lights and running lights all work except the brake lights will not.
When unhooked, all the lights work on the tow. I've checked with another tow vehicle and the same problem occurs.

[Capt Bravo]

When the tow vehicle is hooked up to the motor home, directional lights and running lights all work except the brake lights will not.
When unhooked, all the lights work on the tow. I've checked with another tow vehicle and the same problem occurs.

[paz]

Capt Bravo, welcome to iRV2.

The first thing I would do is check the plug on the back of the motorhome with a volt meter or test light to make sure there is an electrical signal when the brakes of the motorhome are applied.

If there is no signal, then there is a wiring problem in the motorhome. If there is a signal, then the wiring problem is somewhere from the receptacle on back.

I had a similar problem once, except it was a turn signal that didn't work. Turned out a wire had pulled out of the back of the connector on the pigtail that connects the toad to the motorhome.

Good luck and let us know if you find the problem.

[wilanddij]

Do you know for sure that both toads are wired the same? Are you using a diode setup or a separate bulb setup?

When you checked the second toad, did you also use a different cable? If not, then you still have two possible sources of the problem - MH or cable. If you changed both cable and toad, chances are the problem is in the MH.

Also, is your cable one of the 6-pin blue coiled ones that are sold as part of a Blue Ox kit? If so, take the backshells off both connectors and ensure that all of the little set screws inside are securely holding the wires in the correct connector pins.

[GaryKD]

Consider this is a cheap and simple suggestion. The umbilical cords have a history of coming loose at the connections. Take the connection apart and ensure the wires are tightly connected to the plug. The wires slowly come loose and can cause problems with many different symptoms. This task is on my annual maintenance list.

[Rapid Ray]

I had a wild problem with tow lights. They all checked out from the motor home connector to the toad plug to the lamps... however when all pluged together I lost the ground and the electricity went all over to find the best ground. The fault was the ground pin on the motor home needed to be expanded to meet the sides of the plug. There is a slit to spread each pin..... so check for continueity thru each connection point.

[Rnicfingrp]

Go to etrailer.com. They have wiring diagrams and a FAQ for just about any problem a person experiences. The charts have the wire colors as well as connector diagrams as to what pins/blades do what. Great help for me. They will also answer your own individual questions if you can't find your answer on the FAQ.

[Capt Bravo]

Thank your for all the suggestions.
The plugs were checked on the motorhome and both towed vehicles. A broken prong was discovered on the first towed vehicle and the plug was replaced. But the problem still continued. This gave me an opportunity to check the wiring, lights, diodes, etc. on the tow vehicles and everything was OK.
Wiring was being checked on the motor home when I remembered that several years ago a factory tech (the factory is now closed) telling me to turn the chassis power off, than on. This will reset the computer. I did, and everything now works. I wish I had remembered this earlier.