Upgrading the TT electric brakes.

[ROBERTSUNRUS]

Hi, HowieE. On Fords with the factory tow package , they have relays to carry the load to the trailer connector. This puts no additional load on the switches. On my brother's class "A" motorhome his ignition switch and connectors melted. [just repaired today] GM said it was Fleetwoods fault for the overload, but GM will sell him an upgrade kit, with relays, to repair it with.

[HowieE]

Originally Posted by ROBERTSUNRUS

Hi, HowieE. On Fords with the factory tow package , they have relays to carry the load to the trailer connector. This puts no additional load on the switches. On my brother's class "A" motorhome his ignition switch and connectors melted. [just repaired today] GM said it was Fleetwoods fault for the overload, but GM will sell him an upgrade kit, with relays, to repair it with.

For the cost of a $5.00 relay GM and Fleetwood would run the risk of a fire. I have see the same thing with the Sprinters motor homes. Both sides blame the other when the light fail.

Keep in mind the so called up grade, if it is the kit I metioned above it uses the same size wire as the original. Also it is not color coded, all white wires. I would suggest you relay the marker light load off a seperate circuit.

As for Ford I am about to upsize the brake light wiring in my just purchased 2004 Excursion because of excessive voltage drop in the barke circuit from the controller to the trailer connector.

[Zeppelinium]

You can see the Ford approach in the schematic at the bottom of this post (note the use of relays, as previously mentioned above):

http://www.airforums.com/forums/520826-post6.html

The table in the same graphic has information on wire gauges and maximum currents, but I would recommend many of their wire gauges be heavier by one step.

The brake discussion is interesting because they work on current and as long as you can lock up the brakes at some high setting of the brake controller, it doesn't matter if you lose a little voltage in the wiring. Maybe that's a good diagnostic--if you can't lock the brakes even at the highest controller setting, either you have a weak controller or your wire is too small (it could be the wire to the controller, from the controller to the 7-way connector, or the wiring in the trailer).

Zep