Installing a Tekonsha P2 Electric Trailer Brake Controller # 90885 on a 2004 Hummer H1

Question:

I own a 2004 H1 Hummer. I want to install a P2 trailer brake control. Will it hard wire or quick connect into the factory wiring harness? My hummer has the adventure package which includes a heavy tow hitch and 7 pin connector. What should I purchase to work with the factory harness?

asked by: Gary T

Expert Reply:

To install the Tekonsha P2 Brake Controller # 90885, in your 2004 Hummer H1, you will need to do a little hardwiring, but since you already have a functioning 7-Way trailer connector, there will not be too much work involved to get it installed and ready to tow.

First, you will need enough wire # 10-1-1 to reach from the 7-Way trailer connector at the back of the H1 to the cab of the vehicle where you plan to mount the brake controller. This wire is sold in 1-foot increments. I recommend about 25 feet. If there is extra wire it will be needed.

Connect one end of the wire to the brake controller blue wire. You will then need to route the wire through the firewall and under the vehicle to the 7-Way trailer connector. Make sure to avoid areas that might pinch or burn the wire. You can use wire ties to attach the wire to existing wiring under the vehicle. Once at the 7-Way, clip off an extra wire. Attach the end of the wire to the pin in the 7 o'clock position (if looking at the back of the 7-Way). With that connection made, return to the brake controller in the cab.

Next, you will need to attach the white brake controller wire to a ground point or bare metal surface in the cab. Or you can route it through the firewall and connect to the negative battery terminal. Next, attach some of the extra wire to the black brake controller wire and route it through the firewall and over near the battery. Find a place to mount a 20- or 30-amp circuit breaker (see brake controller instructions for which size to use).

The wire will need to reach this circuit breaker, Cut off any extra wire. Once the wire is attached to the circuit breaker, attach another length of wire to the pole labeled BAT and attach it to the positive battery terminal. For a 20-amp circuit breaker use # PK54520. For a 30-amp circuit breaker, use # 38630.

In the cab, there is just one remaining connection. Using a circuit tester like # ALL640595, find the wire on the brake switch located above the brake pedal that carriers a signal ONLY when the brake pedal is pressed. If the wire has a signal at any other time (like when the lights are on or turn signal is engaged) it is the wrong wire. Once you find the wire attach it to the red wire on the brake controller. That will conclude the installation.