Proper Brake Controller Wiring Harness for a 2005 Class C Motor Home On a E Series Ford Chassis  

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Expert Reply:

Connecting a brake controller on your E series, van chassis, motor home can be done one of two ways. You can use the brake controller connector, item # 3035-S, to connect to the connector under the dash, if it is supplied, or you can hard wire the connector. From the pictures you sent it looks like the connector that is not in use could be the correct connector. The connector that is in use looks very similar also and is in the normal location that our installer said the connector should be found so it may be the one that is needed but is being used for some other function on the motor home.

I would start by using a circuit tester, item # PTW2993 if needed, to test the terminals in both connectors. Start with the connector that is not in use. Position the vehicle connector with the locking tab and the two insertion slots to the left (similar to the position in the picture that you sent) and you should have 12-volt constant power on the bottom right terminal, and you should get power when the brake pedal is pressed on the bottom center terminal. The brake output is in the bottom left position and the ground is in the top left position. The top right and center posts are not used for brake controller wiring.

If you find that neither of the connectors you took pictures of is the correct connector for brake controller installation then you can hard wire a brake controller. You will need to find the cold side of the brake pedal switch under the dash. This circuit has 12 volts power on it only when the brake pedal is pressed. I have posted instructions for hard wiring a brake controller below.

Since you have a 6-Way at the rear of the vehicle you can add or switch to a 7-Way and 4-way connector using the Adapter 4 Pole to 7 Pole and 4 Pole, item # 37185. You will just have to remove the 4-Way connector on the back side of the connector and splice the correct circuits to the existing wiring, by function. If you have to hard wire the brake controller you may need to run a separate brake feed wire to the blue brake feed wire on the adapter.

If your tow dolly has surge brakes you may need to use the center pole on the 7-Way connector as a reverse lockout circuit. If so you will need to locate the reverse light circuit behind one of the tail lights and connect that circuit to the center pole on the 7-Way connector.

expert reply by: Robert G

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