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Hardwiring a Brake Controller on a 2001 Chevy Blazer without a Factory Tow Package


i cant find the electric brake wire and the 12 volt power lead location outside the firewall to connect the electric brakes


Expert Reply:

The reason you cannot find the 12 volt power and the electric brake wire is because you have to hardwire them yourself.

On your 2001 Chevy Blazer, you will have to hardwire the vehicle to install a brake controller. Hardwiring a vehicle may seem like a difficult task, but it really is not too hard. I can guide you through the process.

You will need three items in order to install the brake controller. First, you will need the brake controller itself. Second, you will need a 7 and 4 Way Installation kit, # ETBC7. Last, you will need Draw-Tite Wiring, # 18252.

First of all, you will need to install Draw-Tite Wiring, # 18252. You will need access to the taillight wiring to install this harness. Using the included circuit tester, you will need to find the functions of the taillight wiring. Turn the key on (starting the Blazer is not necessary) and turn on the left blinker. With the tester, find the wiring that causes the tester to blink with the turn signal. Attach this wire to the yellow wire on the harness. Next, move on to the right turn signal and find the wire that flashes with the signal. Attach this wire to the green wire on the harness. Then, turn on your lights and find the wire that carriers a constant signal. Attach this wire to the brown wire on the harness. The white wire on the harness is the ground. Attach it to an existing ground point or attach to the vehicle frame. You can route the 4-pole anywhere at the back of the vehicle. The 4-Way part of the ETBC7 kit will plug into this 4-Way connector.

Next, you will need to install the 7 and 4 Way installation kit, # ETBC7. This kit allows for a 7 or 4 pole connection at the rear of the vehicle. It plugs into the 4 way you just installed and connects to the brake controller and vehicle battery.

If you are fairly experienced with automotive or electrical projects, this should not be too hard. I will provide a brief outline here.

Starting with the ETBC7 kit, after installing the 18252, ground the 7-Way white wire onto the vehicle frame. Connect the black wire in the grey duplex cable (included with the ETBC7 kit) to the black wire on the 7-Way. Then connect the white wire from the duplex to the blue wire on the 7-Way. Next, you will route the duplex cable under the vehicle to the engine compartment.

Next, mount the brake controller where you will have easy access to it using the bracket and screws provided.

Last is to make the connections from the brake controller to the vehicle. On the duplex cable, now under the hood, separate the white brake wire from the 12-volt black wire. The white wire gets routed through the firewall, under the dash, into the vehicle. This wire connects to the blue wire from the brake controller. The black wire gets connected to the positive battery terminal via a 40 amp circuit breaker. Mount the circuit breakers under the hood or dash then route the black hot lead to the 40 amp breaker via ring terminals, and then to the positive battery terminal.

The black wire on the brake controller connects to a 20 or 30 amp circuit breaker (see the brake controller instructions for which circuit breaker to use) and then to the positive battery terminal. Route the brake controller white wire to the negative battery terminal. From the wires connected to the brake switch at the top of the brake pedal, find the wire carrying a signal only when the brake pedal is engaged. You will need a circuit tester like # 40376, or the one that came with the 18252 harness. Connect that wire to the brake controller red wire. I have also included 2 videos that show the installation of an ETBC7 kit.

That is pretty much it. I have included an FAQ on wiring a brake controller from scratch that contains a little more detail.

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