No Green Light on Tekonsha PowerTrac Brake Controller 39523 When Trailer is Connected  

Question:

Expert Reply:

First, confirm that there are no other items that generate radio frequency interference (RFI) mounted within one foot of the controller; items such as cell phones and CB radios can interfere with its operation and could affect the display.

(Also, if you happen to have a breakaway switch on your trailer, take care that you do not ever test it with the trailer connected to the vehicle as this will damage the controller. Ensure it is wired correctly since reversed connections to the breakaway battery will also damage the controller.)

The indicator LED should be:

Green when the trailer is connected and with NO brake applied;
Red when the trailer is connected AND the brake is applied;
Flashing Red or off when trailed is not connected.

If the green light does not come on when the truck is on and the trailer is connected, this means that the brake controller is not seeing that the trailer is there. This can mean there is something wrong with the brake controller, the trailer or both. So, the first thing to do is to eliminate one possibility. You will need a circuit tester such as # PTW2993.

Turn on the truck, and with someone in the vehicle, touch one end of a circuit tester to the ground pin, 7:00 position, on the 7-Way at the rear of the truck. Touch the other end of the circuit tester to the brake controller pin, 5:00 position. At this point the green light should come on indicating that a trailer is connected. Have the person in the truck press the brake pedal to activate the brake controller. This should cause your circuit tester to light up or beep. If everything works, then we know the problem is on the trailer. If it does not work as described above, then you need to check the ground wire on the 7-Way, and inspect all connectors for signs of any green or white corrosion.

If the 7-way is an OEM part its age may be the problem. Sometimes corrosion can work its way into the wires from the connector pins. This is not uncommon. If you see any signs of corrosion you might need to replace your 7-way, using part # 20137.

The next step would be to check the trailer. Check the ground wire for the trailer connector. Make sure the connections are clean and secure, and that the wire is not pinched or frayed. Next check the trailer brake magnets. They will have two wires, one connected to the trailer frame for a ground, the other connected to the blue brake controller wire. Make sure both of these connections are solid. Trace the blue brake controller wire back up the trailer frame and check it for nicks in the insulation. Even tiny gaps in the insulation can lead to a short.

Next check the brake magnets. If you can see the copper windings then the magnets are bad and need to be replaced. They may also have a short in them. Take an ohmmeter and touch one end to one of the magnet wires and the other to the other magnet wire, with the trailer disconnected. If your brakes are 7 inches then your you should see 3.8-4.0 ohms, if you have 10-12 inch brakes, then you should see 3.2-3.5 ohms. I have included an article on testing brake magnets.

Once you find and correct the problem an application of dielectric grease to all connections is a good way to prevent future issues. We offer part # 11755.

If none of the above lets you isolate and correct the problem, please let me know.

expert reply by: Adam R

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