I tested between the ground prong and the brakes prong with the manual lever all the way over and go 13.5 volts. With the controller all the way up and the brakes pressed I got 4.5v. Seems to be a controller problem maybe.

 

I don't think it's the trailer because it works great on another truck.

 

I'll run out and check what mine reads.....

 

I have the one with the **** and lever, it's probably 5 yrs old.

How much is the P3?

 

Mine reads about the same. Output voltage 3.3 volts, with manual lever 10 volts, battery voltage 13.5. the gain was set at 8.

I bought the P3 when my camper brake probems started, thought it might be the brake controller. I was wrong (it wound up being 2 magnets) - but the P3 has some troubleshooting screens that show, voltage, amps, battery, etc. Made it easier to troubleshoot for me. Ran about $130. Her'e a link to one site:

Tekonsha P3 Brake Controller - RV Parts, RV Supplies & RV Accessories for 5th Wheels, ToyHaulers, Campers

 

Here's another link that shows the display features. Makes it easier to troubleshoot - that's for sure.

Tekonsha P-3 Trailer Brake Controller - Proportional 90195 : Trailer hitch bike rack and trailer hitches - etrailer.com

 

Rich,
What magnets are you talking about?

Thanks for the help and the link. Reps coming your way.

 

Sorry to do the "Death by links" on this thread. But here is another link. Shows the brake magnets in the 3rd & 4th pictures. They ussually run $30-40 each and take about an hour to replace on each wheel. If your gonna dig that deep you might as wee inspect & repack the bearings while you are in there.

again, not sure if this is your problem also - but it was mine......

http://www.etrailer.com/mm5/graphics...bc/blue_tn.jpg

 

Still betting on a grounding problem. Trailer working fine on another truck kinda rules out trailer. Check voltage between 12 volt constant and ground while moving wire spicing around and see if it falls below 12-13volts. Also under the hood is the 30amp trailer brake fuse, don't think that's a problem, but check it anyway. Fuse #28 is the one.

 

If you can, hook up the trailer to the other truck this week and see if it still brakes the way it did previously.

 

Barry tell me if I did this right; I checked the volts between the 12v pin and the ground pin and got almost no volts with the truck running. I also tried to ground the meter on the frame and tested the 12v pin and got nothing. What do you think?

 

I don't mean to answer for BArry but you should be getting a 12V+ reading testing the way you did. Check the fuse like Barry suggested.

 

It is sometimes hard to make ground to the frame unless you find clean metal. The low voltage could still be from a bad ground. Make sure and check fuse #28 under the hood to make sure. Recheck against frame if you scratch a clean place where you see shiny metal and if you still have low voltage, the you have some bad connections somewhere. Is your harness a cut and splice connection? Of does it plug into the truck harness?

 

Hey Jason,

I've dealt with lots of trailer brake issues.

The trailer brakes work with drag magnets in the drums. The magnet drags the inside face of the drum, opposite of the wheel mounting. The more current that is allowed through the harder they pull to the inside of the drum. The drag between the magnet and the drum moves a lever that applies the shoes to the friction surface of the drum.

There are two things. Sounds like you don't have the factory wiring on this truck. The connections could be weak cutting the available current at any given setting. Similarly the wiring could be in insufficient requiring more voltage to get the same current. Unfortunately that is one variable that is hard to determine.

What I would do is measure the voltage available to the brakes on both trucks with the same settings between the blue brake wire and ground. You can take different readings, say at 1/2 gain and full gain and compare them. This may give some insight as to the issue. If the wiring or controller on your truck isn't able to supply the same amount of current at similar settings, the voltage reading will be proportionately lower since the brakes will be using more of the available current, thereby drawing down the voltage. Of course you have to check the ground side too, since a faulty connection will limit the amount of current that can flow as well. The voltage on your truck will be higher than the other truck in that case since there is "excess" potential on the feed side of the circuit.

There should be a ground from the trailer connector on the truck side to the truck frame. The brake controller should also have a ground as well, that is part of the truck connector normally but who knows if yours has been spliced in. You can take a resistance reading from the truck connector to the frame, as well as from the wiring from the prodigy to ground. This will tell you where the ground issue is. Keep in mind it could be a white wire on the Prodigy, and certainly should be on the trailer connector.

 

Fuse is good, I will try grounding to the frame where I grounded my backup lights.