Troubleshooting Tekonsha Prodigy P2 Brake Controller # 90885 Installation in 2007 Nissan Frontier  

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Helpful Expert Reply:

Thank you for your recent purchases from etrailer.com. I see that you selected the excellent Prodigy P2 # 90885 which is highly rated by our customers and that has proven to be exceptionally reliable.

There are two possible mis-wire conditions that could cause your trailer's brakes to lock up; incorrect hard-wire connection at the under-dash connection point and a mis-wired 7-way trailer connector.

In the passenger compartment the red wire from the P2 should connect to the cold side of the brake light switch; this is the wire on the switch that carries voltage ONLY when the brake pedal is actually pressed. If the wrong wire from the switch is connected to the controller, then the P2 will receive a continuous 12-volt signal that will fool the controller into thinking that you have stepped on the brake pedal. You can use a circuit tester like # PTW2993 to find the brake switch wire that carries voltage only when you step on the brake. If you are using a quick-connect harness to plug in under the dash, then there is an outside chance that the harness itself was mis-wired. Use the tester on the port's pins to verify that one pin has 12V power all the time (this pin should feed the black wire) and that another has 12V power only when you press the brake pedal (this pin should feed the red wire). Re-position the connector's pins if necessary.

Another possibility is that the 7-way connector at the rear bumper is not wired correctly. If the 12V signal wire (for the trailer's auxiliary power feed) were connected to the pin for the brake circuit, this would cause the trailer brakes to receive full power all the time. You can use the circuit tester to check the signals at your 7-way to ensure the correct signals appear at the connector. Please refer to the linked photo that shows the typical function assigned to each pin on a 7-way. The pin at the 5-o-clock position should have a signal ONLY when you step on the brake or press the manual override on the P2.

You can also check your trailer's wiring to be sure there is no mis-wire condition on the trailer connector.

Another possibility is that the power or boost settings on the controller are too high or that your brakes themselves are not adjusted properly.

I have linked an article on troubleshooting brake controller installations for your reference.

expert reply by: Adam R

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