Troubleshooting 2009 Ford F-150 OEM Brake Controller Not Sending Much Power to Trailer Brakes

Question:

Can you please help me. I’ve installed a 2009 ford f150 OEM trailer brake controller the wiring harness was behind the little covey compartment. I plugged it in but am not getting any lights or message saying trailer brake fault on my instrument panel. So I’ve tested all my fuses related too trailer brake also moved relays around to just to see if it might be a relay problem. But it made no difference. So I pulled the dash and center council again took the controller back loose and tried to test the wiring harness all I’m only getting about .20 volts. And at the back at the 7 pin I tested all those with the truck running and the brake applied also cked the reverse. All pins gave about 14 volts except the pin labeled electric brakes it only gives .20 volts. Is the controller bad or the wiring harness not getting any power???

asked by: Todd W

Expert Reply:

The OEM Ford controllers are essentially the Prodigy P2 # 90885 and P3 # 90195 brake controllers but repackaged to fit that cubby you're talking about.

These controllers are proportional so if you were testing the power to your trailer brakes by sitting parked and pressing the brake controller then the brake controller won't be sending much power since it can tell your trailer isn't moving. What you need to do is apply full power by using the manual override. This will send full power back to your trailer brakes and you'll know if the controller is actually connected properly or not.

Once you've tested this you can then take your trailer to a big open space like a parking lot and dial in how the proportional braking will work. Make your adjustments until the trailer brakes like you want it to on the road and you'll be good to go!

expert reply by: Jon G

Stephen

2/1/2025

Hi' i have a 2009 f150 5.4 FX4 with factory towing. I installed a OEM brake controller and the only way to apply brakes to trailer is to manual the gain settings by hand.The truck brake pedal does nothing. Trailer brakes do work if i do the above. Thank's for any help at all.

Jon G.

2/3/2025

@Stephen Thanks for the information. So, we know the manual override works, have you tried taking your towing rig to an open parking lot and applying the brakes with your pedal while in motion to see if your trailer brakes are activated then.