Brake Controller Help Please (Non Toyota controller)

Looking for any advice from some experienced towers....

Truck: 2007 5.7 Crewmax

I just got a new 24' trailer (about 7000lb). I have factory wiring for brake controller. I have a Tekonsha P3 controller installed.

Here's the problem: At max gain (and boost level 3) I cannot get the tires to lock up.

Got my buddies Ram 3500 to pull it, cannot get brakes to lock up when maxed out.

Take the trailer back saying that I suspect the brakes are not set correctly on the trailer.

They call me today and say nope, brakes all good they tested them. I asked if this included a road test, they said yes, but I wasn't there so who knows if they actually drove it around.

How can it be that with two different controllers no lock up? And just for reference, when I had this controller in my Tacoma I was able to lock up brakes at about mid-boost settings on two different trailers, although they were 4500 lbs and less.

As this is a proportional controller, does is even make any sense to put a meter on the pins at the connection to see what sort of voltage I am getting when brakes applied?

I'm scheduled to go get it tomorrow and they said they need to look at my truck ($$$).

I was thinking I should ask them to hook up a similar trailer to mine so I can go drive it around and see if I can get the brakes to lock up on it.

Any thoughts or advice from anyone?

There's a Canadian beer in it for those who help. (But watch out, up North we make some strong brews!)

 

Had a P3 that I used on my Last Tundra. Set on B2 it would Not lock the trailer tires up. Trailer was a 25 Ft travel trailer that weighed in at about 7k loaded. I suspect that the added weight of the Tundra combined with the Larger trailer may be to much for the Trailer brakes alone to lock up. Again I'm just speculating here. Doing a brake test with mine, it would definitely tug heavy on the truck. Not sure that I would want the trailer tires to lock up,but just do a well controlled stop. JMO Also if the trailer is new, there may be a Break-in period for the brakes to seat properly. Again JMO

 

Apply the trailer brakes with the manual lever, and measure brake signal voltage on the blue wire out of the controller with the trailer connected.

You can also measure the voltage going into the brake magnets on the trailer the same way.

I agree though, locking the wheels is NOT your goal, and trailer brakes do need a thousand miles or so to wear in for good braking.

 

I’m having this exact issue with my 2014 with a P3 also. Did you ever find the cause and fix? Thank you in advance!

 

Check the voltage on the blue wire with a meter. It should be ~13.5 Volts. If you have that at the controller, check at the connection at the back of the truck. Should get same reading.
If that is good check and adjust your trailer brakes until there is light drag with the wheel suspended turning by hand.
If that is good, connect the trailer and check voltage at the brakes by piercing the wire jacket with the tip of your meter at the trailer brakes, your black lead should be grounded on the frame of the trailer, an Unpainted surface. Again you should have 13.5 volts.

 

If you are getting the same or close to the same voltage at the trailer connector under load, the problem is your trailer. The truck cannot produce more than 13.5 volts or so.

With the trailer connected, have a helper hold the brake controller at max output. The p3 has a mode to tell you how many volts are being sent. Then test the voltage at a wire junction on the trailer as close to the truck as possible. There is probably a splice on the tongue somewhere.

 

Try locking them up manually in a dirt patch, less friction.

 

Yes, it was a wierd one. Turns out, my trailer arrived at the dealer on a flat-bed, rather than being towed. So normally, the brakes are all broken in on the trip to the dealer. Mine had never been used. After a few hundred km, the were lockable as one would normally expect.

Took the dealer a bit of digging to come up with that info!