Trailer brakes -- good news and bad news

[cwilly8]

Thinking that the brakes on our 2015 X-23B are shot, I took it to a local trailer shop yesterday to have whatever was needed done to make them completely functional, expecting to pay several hundred dollars (or more) to have the work done. They used their test box and determined the brakes are functional. "The problem is with your truck," they said. So the good news is we don't have the brake work expense to deal with.

The bad news is that I have a new issue to troubleshoot. We have a 2018 Dodge Durango with the factory tow package (no built-in brake controller). We added a Prodigy P3 controller, connected to the vehicle via a cable that plugs in under the dashboard. All the lights on the trailer work correctly through the 7-pin connector at the rear of the vehicle. But the trailer brakes are ineffective, not even holding the vehicles stationary at idle. With the shop’s test box, the trailer brakes brought us to a stop from idle.

It would seem that the problem is either with the Prodigy brake controller or the connecting cable. Any suggestions on troubleshooting from this point? Thanks!

[mini4mw]

The Prodigy P3 has a slider on it to manually activate the breaks. If you slide it to activate the brakes, does anything happen? Have you adjusted the force the Prodigy sends the brakes? In the manual there's a setup section to select proper trailer weight and size so the unit sends the proper signal (voltage?) to the trailer brakes. Too much and it locks the trailer brakes. Too little and it does nothing.

[cwilly8]

Sorry, I should have stated that the brakes worked properly in the past. With the manual lever pushed all the way over, the brakes have little or no effect on stopping the trailer. I have been through the setup to make sure the correct settings are there.

[Onyrlef]

Originally Posted by cwilly8

Sorry, I should have stated that the brakes worked properly in the past. With the manual lever pushed all the way over, the brakes have little or no effect on stopping the trailer. I have been through the setup to make sure the correct settings are there.

"Little or no", makes a huge difference which. Occam's Razor holds that the solution to most problems is in starting with the simplest and working toward the least likely but still possible and likely most complex cause. If you know it's not in the trailer, then the next most likely culprit is the 7 pin connector (s). I'd have someone activate the brakes and with a tester touch the brake pin (#2 pin, blue wire) and ground and see if it goes hot. It shouldn't, but if it's hot, the culprit may be the female from the trailer. If it's not hot, check the blue (brake wire) connection to the 7 pin. and work back toward the controller from there. These things can be real head scratchers.

[cwilly8]

I got under the trailer while my wife actuated the lever on the controller. I could hear a hum as she hit the lever. So my uneducated conclusion is that some power is making it to the brakes, but apparently not enough to do the job!

[Onyrlef]

Originally Posted by cwilly8

I got under the trailer while my wife actuated the lever on the controller. I could hear a hum as she hit the lever. So my uneducated conclusion is that some power is making it to the brakes, but apparently not enough to do the job!

Okay, next up, check for a bad ground.

[Murff]

Originally Posted by Onyrlef

Okay, next up, check for a bad ground.

I second this! Same problem on our last rig. Ended up replacing the pigtail on the trailer.

Murff

[madmaxmutt]

Originally Posted by cwilly8

Thinking that the brakes on our 2015 X-23B are shot, I took it to a local trailer shop yesterday to have whatever was needed done to make them completely functional, expecting to pay several hundred dollars (or more) to have the work done. They used their test box and determined the brakes are functional. "The problem is with your truck," they said. So the good news is we don't have the brake work expense to deal with.

The bad news is that I have a new issue to troubleshoot. We have a 2018 Dodge Durango with the factory tow package (no built-in brake controller). We added a Prodigy P3 controller, connected to the vehicle via a cable that plugs in under the dashboard. All the lights on the trailer work correctly through the 7-pin connector at the rear of the vehicle. But the trailer brakes are ineffective, not even holding the vehicles stationary at idle. With the shop’s test box, the trailer brakes brought us to a stop from idle.

It would seem that the problem is either with the Prodigy brake controller or the connecting cable. Any suggestions on troubleshooting from this point? Thanks!

What power level is set on the P3, currently? Have you tried raising that level?

[cwilly8]

Originally Posted by madmaxmutt

What power level is set on the P3, currently? Have you tried raising that level?

The controller is set at B1 and max output (14).

[mini4mw]

Getting harder to troubleshoot this one..

bad ground (dirty, corroded) or Prodigy is what i'm guessing. I'd put more weight in the wiring issue.

Since the shop checked the trailer and it worked, I'd do the below in the truck. I'd still see if you can verify the shop's testing and hook your truck up to a trailer with brakes and see what you get and someone else to your trailer and see what they get. If the shop was right, the other truck will work with your trailer and you won't work with another trailer. I'd be a millionaire if I had a dollar for when someone said X worked and I was looking for a problem in the wrong place.

I'd check the 7pin, clean it out (wire brush) as best as possible and get some dielectric grease and see if that helps. Looking for ground connection, partially cut wire or something else impeding current flow. If you still don't see anything, you could pull the pig tails from Prodigy looking for loose/frayed connections.

I'm assuming the Prodigy says a trailer 7pin is connected when it is and gives you the red screen when you start the car up and one is not, right?

[cwilly8]

Originally Posted by mini4mw

bad ground (dirty, corroded) or Prodigy is what i'm guessing. I'd put more weight in the wiring issue.

Since the shop checked the trailer and it worked, I'd do the below in the truck. I'd still see if you can verify the shop's testing and hook your truck up to a trailer with breaks and see what you get and someone else to your trailer and see what they get. If the shop was right, the other truck will work with your trailer and you won't work with another trailer. I'd be a millionaire if I had a dollar for when someone said X worked and I was looking for a problem in the wrong place.

I'd check the 7pin, clean it out (wire brush) as best as possible and get some dielectric grease and see if that helps. Looking for ground connection, partially cut wire or something else impeding current flow. If you still don't see anything, you could pull the pig tails from Prodigy looking for loose/frayed connections.

I'm assuming the Prodigy says a trailer 7pin is connected when it is and gives you the red screen when you start the car up and one is not, right?

I had not thought of connecting to another trailer. My father-in-law has one across town. We are away from home for a couple of days, but I'll hook up to his trailer when we can and see what happens.

Yes, we get the green screen showing trailer is connected.

[craigav]

Originally Posted by cwilly8

I had not thought of connecting to another trailer. My father-in-law has one across town. We are away from home for a couple of days, but I'll hook up to his trailer when we can and see what happens.

Yes, we get the green screen showing trailer is connected.

If you have a partner that can help you and a voltage meter, then you can check the voltage at the vehicle side connector at the Brake Controller output terminal. You should have no voltage with the controller not activated and increasing voltage as the manual brake controller lever is slid over to the full braking side which should be the full voltage (whatever the battery voltage is). ~CA

[BuddyRay]

Back when I towed with a older truck without factory brake controller I went through three Prodigy controllers. They kept burning out and two of the three exhibited the symptoms you are describing - they would send power to the breaks, just not enough.

Don't ask me why I kept buying the same controller - it had to do with lazyness - I didn't want to change the mounting bracket and wiring harness.

[Onyrlef]

Originally Posted by craigav

If you have a partner that can help you and a voltage meter, then you can check the voltage at the vehicle side connector at the Brake Controller output terminal. You should have no voltage with the controller not activated and increasing voltage as the manual brake controller lever is slid over to the full braking side which should be the full voltage (whatever the battery voltage is). ~CA

That would narrow it down for sure and especially before tearing into the harness.

[cwilly8]

I checked the vehicle side connector pins with a voltmeter. All of the non-brake controller pins measured 12.2 to 12.5 volts. The brake controller output was 11.95 volts, which is what it should be. All of the pins were shiny clean and I could see the dielectric grease inside.

This leaves me perplexed, because the trailer shop plugged their test box into the trailer side connector and the brakes worked. That means from the controller to the vehicle connector works and from the trailer connector to the brakes works.

That leaves the actual connection from our vehicle to the trailer. When plugged together, all the other pins work (running lights, left and right turn/brake lights, and back-up lights.) I will clean all the contacts on the trailer side to see if that makes a difference.

If not, then I will take our Durango to my father-in-law's trailer to see if the controller works with his trailer brakes.

[Yooper906]

[QUOTE=cwilly8;1052789]
This leaves me perplexed, because the trailer shop plugged their test box into the trailer side connector and the brakes worked. That means from the controller to the vehicle connector works and from the trailer connector to the brakes works.

/QUOTE]

Magnet brakes can certainly be perplexing. The shop I used to work at I had the tools to measure voltage on the magnets first, then amperage. Each wheel should be getting around 2.5 amps. Ten amps for a 4 wheel trailer. I've seen bad magnets that show 12 volts or over that are bad, as in little amperage. An amperage check really is the way to go. Or if you want to have a little fun while drinking a cold one, put the trailer on jacks, take off the wheels and drums, have someone adjust the brake controller in the truck while watching how long a pair of pliers or something will stick onto the magnet. LOL

[cwilly8]

/QUOTE]

Magnet brakes can certainly be perplexing. The shop I used to work at I had the tools to measure voltage on the magnets first, then amperage. Each wheel should be getting around 2.5 amps. Ten amps for a 4 wheel trailer. I've seen bad magnets that show 12 volts or over that are bad, as in little amperage. An amperage check really is the way to go. Or if you want to have a little fun while drinking a cold one, put the trailer on jacks, take off the wheels and drums, have someone adjust the brake controller in the truck while watching how long a pair of pliers or something will stick onto the magnet. LOL[/QUOTE]

I found in the Prodigy P3 instruction sheet that there is a Troubleshooting Mode that will display voltage and current output. Has anyone tried that with their rig?

[cwilly8]

Cleaning the pins and ensuring I got a snug fit from vehicle-to-trailer connector didn't seem to make any difference. Our driveway is a slight slope, and the trailer brakes wouldn't even hold with the vehicle in neutral (moving the controller lever all the way to the left). Next stop - father-in-law's trailer.

[Onyrlef]

Originally Posted by cwilly8

Cleaning the pins and ensuring I got a snug fit from vehicle-to-trailer connector didn't seem to make any difference. Our driveway is a slight slope, and the trailer brakes wouldn't even hold with the vehicle in neutral (moving the controller lever all the way to the left). Next stop - father-in-law's trailer.

Haven’t been keeping up, did you ever check the output at the brake pin on the 7 way, #2 @ 7 o’clock?

[cwilly8]

Originally Posted by Onyrlef

Haven’t been keeping up, did you ever check the output at the brake pin on the 7 way, #2 @ 7 o’clock?

Yes, it measured 11.95 volts.