Left turn and Brake Lts not working on tow

[timjet]

The left brake light and left turn signal are not working on the tow car when I tow. The car lights are fine and work when not connected to the coach. The coach lights work fine as well, both when I tow and don’t tow. I bought a Tow Mate which is a light bar that via magnets attaches to a tow car and wirelessly illuminates when I use turn signals or brake. It uses a plug that is inserted into the coach tow plug and wirelessly transmits the signal to the light bar. The Tow Mate does exactly what the car does when its plug is connected to the coach – no left brake and no left turn signal.

I checked voltage on the coach plug. When I press on the coach brake the Left Turn/Stop lights contact located at the 9 O-Clock position reads 0 voltage. When I step on the brake the right turn/stop lights contact at the 3 O-Clock position reads 11.82 volts, as it should.

With the coach brake pedal depressed and the left turn signal on, I get intermittent (blinking) voltage on the tow plug at the 9 O-Clock contact but not 12 volts, more like 4 volts but it’s hard to tell because it’s blinking so fast.

With the left turn signal on (no braking) I get intermittent low voltage on the 9 O-Clock contact.

There is a 10 wire bundle at the rear of the coach. 4 wires go the device shown in the picture below which is a wiring converter and 2 wires go from this wiring converter to the trailer plug.

This wiring converter states: If you have this — the motorhome has one circuit for a brake light signal and another for a turn signal and the towed vehicle has combined brake and turn signal circuit then you need this wiring converter.

I don’t know exactly what I have but I suspect the previous owner had this installed and I don’t need it.
So is my thinking correct, should I remove the wiring converter. Where would the 4 wires going to the wiring converter go, color to color on the trailer plug?

[Lt Dan]

You need the converter and it may be your problem. Check for voltage into the converter, then voltage out. Your motor home has separate turn signals and brake lights which have to be combined into brake light/turn signals for the towed vehicle or trailer. I had the same problem with our Itasca and had to replace the trailer converter.