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subdev · 09-10-2016, 02:58 PM

I have a '08 Hurricane 34B with a factory 4-pin tow package. I am upgrading to a 7-blade plug and am installing a Prodigy controller to pull a tow dolly with elec brakes. Found the harness plug under the dash for the controller after a lot of searching! Underneath the chassis, just rear of the driver's seat, are two exposed wires strapped to a larger harness. One white and one blue. Both are terminated with butt connectors. I presume that the blue wire is the brake control wire, but I'm not sure if the white wire is ground or 12V power? Why would there need to be a ground wire there...what is it grounding, since my new 7-blade plug has it's own ground wire at the back bumper? If this white wire is a ground, does that mean I have to run a separate power wire from the back plug all the way back up to the battery? Thanks for any help.

l1v3fr33ord1 · 09-10-2016, 07:12 PM

subdev-

It's unlikely that the blue and white wires are related to the electric brake controller wiring.

What are the colors of the wires for the plug you found under the dash? Red, blue, green and white?

I don't have your coach, and I found that the coach manufacturers don't always use what Ford gave them, but... If you look under the coach, inside the left frame rail about 4 to 8 feet from the rear of the coach, you should find two Ford connectors. These connectors contain the wires you seek. If you find the connectors, let us know and we'll go on to how to figure out what's where, there.

You should also call Thor, and get a wiring diagram from them.

subdev · 09-11-2016, 01:09 PM

Quote:

Originally Posted by l1v3fr33ord1

subdev-

It's unlikely that the blue and white wires are related to the electric brake controller wiring.

What are the colors of the wires for the plug you found under the dash? Red, blue, green and white?

I don't have your coach, and I found that the coach manufacturers don't always use what Ford gave them, but... If you look under the coach, inside the left frame rail about 4 to 8 feet from the rear of the coach, you should find two Ford connectors. These connectors contain the wires you seek. If you find the connectors, let us know and we'll go on to how to figure out what's where, there.

You should also call Thor, and get a wiring diagram from them.

Thanks. I did some digging underneath.
So, to answer your first question. The gray harness under the dash connected the controller harness perfectly. The wire colors on the factory plug are red, green, white, brown, and blue with a white stripe. The controller plug has blue, white, red, and black.

I did find two different harness connections near the back of the coach, on top of the rear edge of the fuel tank. They contain a myriad of wires and appear to run rearward into the factory 4-pin plug on the tow bar. (Pic attached)

The controller has power, but displays the "not connected" symbol, even though I plugged in the trailer.

l1v3fr33ord1 · 09-11-2016, 06:20 PM

subdev-

Here are two pertinent pages extracted from the diagram set I've built for my 2008 HR (2007 F-53 chassis).

One page shows the wires to the under-dash connector. The second shows the wires to the two connectors you found at the rear.

On my coach, Monaco elected not to use the wires Ford provided for electronic brake control. With your coach, maybe Thor did use them. There's no way of knowing without some continuity testing between the dash and rear connectors.

If there is continuity, then the brake controller wire is on connector C405 (the larger, 12-pin connector), and on the pigtail that's plugged into that connector. Open the wire bundle aft of the connector, find the blue wire. Test for continuity with the blue wire on the under-dash connector. Using a heat-shrink butt connector, add a 12-gauge wire to the blue wire on the C405 pigtail. Extend the wire to the correct pin on the 7-pin connector (see this link). Terminate the wire there. Done.

If you want, do the same thing for pin 7 on C405 (trailer backup lamp), and you'll have a backup signal should you ever have a trailer that needs one.

The battery charge pin is a whole 'nother kettle of fish. You'll notice Ford does not provide on on either C405 or C406. In fact, they don't provide one on the F-53 at all. They leave that to the coach builder. Interestingly, Ford does provide a charge line on the 7-pin connector for the E-series van chassis used to build Class C coaches.