Prodigy and 2500 wiring

[Rockin]

I finally got to put a trailer behind the truck after installing my prodigy. No luck.

With trailer connected and prodigy plugged in, it shows the two dots (as if no trailer connection) I have full light function and the trailer brakes are fully on.

I disconnected the trailer wire and the brakes are off. (obvious but they function)

I disconnect the prodigy from the wire and still have locked brakes.

I disconnect the wire from the truck's box and still have locked brakes.

I pull the fuse from under the hood and the brakes unlock.

If I use the manual lever (under any conditions) it shows n.c.

I will pull out the install instructions and read further but I am thinking this is a truck wiring problem. Any thoughts?

[HowieE]

If your are using a standard 7 pin trailer plug you can test as follows.
With the trailer disconnected make the following checks on the trailer plug on your truck.
With an annalog voltmeter, I say annalog because a digital has too slow a responce time, connect one side of the meter to a good truck ground.
With an assistant forward and looking into the trailer plug you should see the following functions at these locations. Battery at the pin at 1 oclock, right directional at the pin at 3 oclock, brakes at the pin at 4 oclock, ground at the pin at 7 oclock, left directional at the pin at 9 oclock, and parking lights at the pin at 11 oclock. The center pin is a spare and may also be wired as a ground,
If this all checks out right your truck wireing is set up in a standard way. Go to the plug on the trailer. Test for voltage between a trailer ground and the pin at the 1 oclock position. This should be your trailer battery. Now check voltage between 1 oclock and 7 oclock. 7 oclock should be trailer ground. If you have voltage on the trailer use a piece of number 14 or smaller wire or use a wire with a 20 amp fuse in it, and insert one end into the position at 1 oclock. Touch the wire to position at 9 oclock, the left brake light should come on. Touch the positon at 3 and the right brake should come on. Touch the position at 11 and the parking lights should come on. Last jack up one side of the trailer and while someone spins a wheel touch the position at 7 oclock, this shold be trailer brakes.

[Rockin]

I should also mention, the trailer has been pulled by the owner (and their vehicle) and the brakes perform correctly.

I will do tests on the truck itself tonight. It has the standard 7 wire on the bumper hitch and I recently added the 7 wire in the bed for the goose hitch. The truck came prewired for the bed wiring so I only had to add the plug. I will test both plugs.

[Rockin]

I called Tekonsha tech support. They were pretty confident that it is my 7-6 adapter. I will pick one up tonight and see if it works.

[SFD]

Tekonsha may be right! Something is going to ground which should not or you have the hot wire going to trailer brake instead of charging circuit.

[saywhat]

The cover at the bumper recept. is stamped to show what each of the seven pins represents.Your recept. in the box should be wired the same.Also the wiring harness from the brake controller to the truck differs from the 2002 year to the 2003 year.The end which plugs into the truck has each wire terminal stamped as a,b,c,d,e,or f.The lite blue wire which is for stop signal from truck stop switch to brake controller is on terminal A for 2002 and on terminal D for 2003,probably 2004 also.If you have the 2002 harness just remove the brown wire which is for contoller illumination from terminal D and put the lite blue wire from terminal A in its place.The brown wire is not needed on the Prodigy.

[Rockin]

I used a different adapter. I put a continuity test on each of the connections and they are clearly different. The one I was using doesn't have the center as trailer brakes. That is where the trailer expected it. Once I made this switch, everything worked great. I found a subdivision being built and drove around its empty streets for a while to adjust the controller. It seems to work great.

[arveetek]

You found the problem before I could jump in!

I have found in my trailer shop that there are two different, accepted ways to wire up the 6 way plug used on horse trailers. They're both the same except for the charge and brake wires. They can be reversed quite easily. If you hook up your horse trailer to a truck, and all the lights function properly, but the brakes are locked up no matter what, then the 6 way plug is the culprit. What's happening is that the charge line and brake wire are reversed, causing a constant 12 volt + supply to be sent down the brake wire. Simply reversing the brake and charge wires on the truck or trailer plug will fix the problem.

Casey

[dmaxmule]

Rockin, for the plug adapter that I bought for 1999 dodge 7 pin truck to 6 pin trailer there was instructions on which two wires to switch in order to do what was stated above. However, it seems you done figured this out. If you still got the old plug you could probally switch the wires and have an extra plug adapter. dmaxmule