4 pin elect. Trailer plug to 7 way plug?

[Panfish Pa]

I recently bought my retirement boat, and the trailer has hyd disk brakes and backup lights. It requires a 7 way plug so the reverse light pulse can release the brakes on the trailer.
So my rig is a low mileage 04' 29ft class C Sunseeker, I had hoped there were splicing points in the oem wiring harness in the rear, but I didnt see any while looking under the coach. The only way I can see accessing the tailight/reverse light wires is through a interior bedroom shelf or by removing the actual tailight. So my question is do I need to splice into them or is there a wire run to the rear bumper via the frame? it seem there should be a aftermarket wire harness for this?

 

[Gr8bawana]

Does your Sunseeker have a trailer plug at all? I'm assuming it doesn't or you wouldn't be asking.

 

[Knobs]

Does your Sunseeker have a trailer plug at all? I'm assuming it doesn't or you wouldn't be asking.

From the thread title, it looks like he has a 4-pin trailer plug(?) and he needs to add the wiring to release the brake using the reverse light?

 

[CharlesinGA]

I have heard of needing backup light power to lock surge brake mechanisms so the surge brakes won't work in reverse, that is what the flat 5 pin connector is for, but never heard of this with electric over hydraulic disk brakes........ or does the trailer have SURGE disk brakes?

As far as separate trailer light/brake wiring, I would think that Ford provided that in '03/'04, but it may be bundled into a harness and never finished out by the upfitter, or Ford possibly did not include it.

Charles

 

[Gary RV_Wizard]

I have heard of needing backup light power to lock surge brake mechanisms so the surge brakes won't work in reverse, that is what the flat 5 pin connector is for, but never heard of this with electric over hydraulic disk brakes........ or does the trailer have SURGE disk brakes?

That's what I was thinking - it must be a surge brake system.

According to the 2004 Sunseeker sales brochure, it comes with a 5000 hitch receiver with a 7-pin plug. The center pin may or may not be wired as a reverse light, though. It's considered to be an optional/auxiliary pin.