Master Tow Wiring

I purchased a "Master Tow" tow dolly new two years ago. Occasionally when I apply the brake It will blow the fuse that operates the parking lights on my 2002 Four Winds RV. Recently I was pulling the dolly with my Suburban, and when I braked hard, It would blow the 30amp fuse that runs the headlamps, parking lamps, and interior dash lights. Fortunatly I had enough spare fuses to get me home. The connector on both vehicals is a 4 wire plug. Any ideas on what might cause this, or suggestions on how to fix his would be appreciated.
Master Tow Wiring

It sounds like there is some kind of short between one of the stop/turn lights and the running lights. If the dolly only has a flat 4-way connector and stop/turn/tail lights on it, I would start from scratch. You can buy a complete trailer light kit in most harware stores for under $30.00 and trying to track the problem down will caost a lot more than that.
Master Tow Wiring

Thanks for the advice. I think I will buy a whole new harness and save myself the grief of trouble shooting. Another question. Are those trailer diagnostic/test plugs of any value? or will it just tell me that my brake ligths don't work. I can buy one for $20, but it might be another one of those gadgets I only use once. Please advise.


Senior Member
Master Tow Wiring

I would just use the voltmeter to see if you have an open circuit (broken wire or shorted out), then make sure your wired correctly from vehicle to tow dolly (sometimes the color of wires will not match completely). I got a wiring diagram from Winnebago and then used it to wire my tow dolly (you can change the wires in the connectors of the tow vehicle (my winn) to match up with the dolly wiring connection). Of course, I had to use an adapter to plug into the Winn to make it a four pronger.
Good luck :)