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Unified Tow Brake Installation Supplement

for 2006 and Newer
Toyota 4Runner, FJ Cruiser, and Highlander

1. Cut off the plug on the Violet wire of the Unified Tow Brake (UTB) car harness. Strip wire and crimp a female spade lug, and connect to one of the inputs of the blocking diode.

2. Locate the plug on the left side of the master cylinder that has two large wires and two small wires in it (see photo below). Remove this plug and strip back the loom to expose the wires. The small wire going into the plug on the upper right hand pin should be a Black with an Orange stripe. Cut the Black/orange striped wire and strip and crimp on female spades lugs on both ends.

3. Connect the spade lug on the factory harness end of the cut Black/orange stripe wire to the other input of the blocking diode. Connect the plug end of the cut Black/orange striped wire to the out of the blocking diode.

4. Use black electrical tape to secure the blocking diode to the factory harness. NOTE: Be sure that the diode is secured sufficiently to the harness that the connections to the diode do not break from flexing or vibrating. Install the four wire plug back on the ABS computer.

Attach wires to diode according to the diagram below.


Location of four-wire plug with Black/Orange wire


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Last modified: 08/15/11