Is Roadmaster Diode Wiring Kit # RM-154 Needed When Flat Towing a 2013 Ford Fiesta

Question:

I have a 2013 Ford Fiesta, you must unhook the battery to flat tow. Why do I need a diode kit with battey disconnected?

asked by: BOB L

Expert Reply:

The battery needs to be disconnected when flat towing a 2013 Ford Fiesta with the automatic transmission because the transmission is shifted electrically. If the battery is left connected it could shift the transmission into the wrong gears when being flat towed and damage the transmission. The manual transmission of the Fiesta does not require disconnecting the battery.

The diode kit like the Roadmaster Diode Wiring Kit, part # RM-154, is used to connect your lighting on your RV to the lighting needed on your vehicle being flat towed. Using the diode kit will provide a measure of safety in the event that the battery is mistakenly reconnected while the vehicle is still plugged into the motor home.

There are three options available for lighting when flat towing your Ford Fiesta. The easiest for infrequent towing is the Peterson Tow Light Kit, part # PE26UR you have referenced. This light kit would plug into a 4-Way on your tow vehicle and attaches securely to any metal surface with strong magnets.

The second option would be to use diodes to tie into the vehicles tail light system. If you will be towing frequently, you may want to consider this option which requires wiring the Fiesta permanently for towing, so you can just plug and go without routing wires each time. The Roadmaster Universal Hy-Power Diode Wiring Kit, part # RM-154, will install inline with the vehicles tail light wiring. We have a video installation for you to review and an article explaining how to wire the vehicle.

The third option involves permanently running wires on the vehicle, but does not require splicing into the vehicle tail light circuits. The RoadMaster Tail Light Wiring Kit with Bulbs, part # RM-155, will fit in the red tail light housing on your vehicle and provide functioning tail lights when towing. A 1 inch hole will need to be drilled in the tail light housing to install the bulbs.

I am including a link to a FAQ page on tow bar wiring. This article will help you decide which wiring is the best for your application.