Tekonsha P3 on Early Tacomas?

[Steve R.]

Has anyone installed a Tekonsha P3 controller on a 2004 or earlier Tacoma (V6)? I would like to mount it in the spot for the ashtray. The dimensions seem to check out OK. How easy will it be to connect the lead to the brake switch? Any other suggestions would be appreciated.

[Brian B-P]

Unlike my Sienna (a typical minivan), I would expect the Tacoma (like most pickup trucks) to be prewired for a brake controller. That means four wires under the dash, probably not matching the P3's colour coding at all, but supplying the right wiring connections. Usually, the wires in this type of arrangement end in a receptacle to just plug in the right wiring adapter to the controller.

The output wire of the prewired set under the dash is connected through the factory-installed wiring harness to the location of the 7-pin connector beside the hitch.

Tekonsha offers a Toyota O.E.M. Style Wiring Harness (model 3040), which is supposed to fit 2002 to current Tacomas, and which just plugs in. Even if this isn't right for the actual year, it shows the general style of connection.

[Steve R.]

I believe 2004 and earlier Tacomas were only set up for a 4-pin connector, no wiring for a brake controller. Later models have the 7-pin setup and are pre-wired for a brake controller. The Tekonsha adapter for Toyotas is for the Tundra beginning in 2002 and Tacoma beginning in 2005 according to the manufacturer. Not a big deal though because a universal wiring kit is available that plugs into the 4-pin. The additional wires have to be run separately to the controller, battery, 7-pin connector, etc. It all looks fairly straight forward except for the connection to the brake switch. Anyone with experience in this?

[Byron Kinnaman]

I believe 2004 and earlier Tacomas were only set up for a 4-pin connector, no wiring for a brake controller. Later models have the 7-pin setup and are pre-wired for a brake controller. The Tekonsha adapter for Toyotas is for the Tundra beginning in 2002 and Tacoma beginning in 2005 according to the manufacturer. Not a big deal though because a universal wiring kit is available that plugs into the 4-pin. The additional wires have to be run separately to the controller, battery, 7-pin connector, etc. It all looks fairly straight forward except for the connection to the brake switch. Anyone with experience in this?

It's been suggested in similar situations that you call Tekonsha. They should be able to talk you through the installation.

[Brian B-P]

I believe 2004 and earlier Tacomas were only set up for a 4-pin connector, no wiring for a brake controller. Later models have the 7-pin setup and are pre-wired for a brake controller. The Tekonsha adapter for Toyotas is for the Tundra beginning in 2002 and Tacoma beginning in 2005 according to the manufacturer.

Looks like you have this figured out... the web page for the product just generally says "(2002 to Current) Toyota".

Not a big deal though because a universal wiring kit is available that plugs into the 4-pin. The additional wires have to be run separately to the controller, battery, 7-pin connector, etc. It all looks fairly straight forward except for the connection to the brake switch. Anyone with experience in this?

I've only done my Sienna. If the connection to the brake switch is the wire in question... I found this relatively easy on the Sienna. I suspect that other Toyota models would be similar.

In the Sienna, the switch is easily reachable (by the standards of under-dash stuff), and the wires are openly accessible for clamping on a tap connector (the brake switch connection is the only one of the four for which I consider a tap connector suitable); however, you need to determine which one is the right wire. Without a wiring diagram, I just checked for voltage with a meter to find the pin of the connector which was zero normally and +12V when the pedal is pushed down - as I recall, there was only one.

If you have a credit card associated with a U.S. address, you can buy access to the on-line technical resources on the Toyota website. A one-day subscription costs roughly $10, and while subscribed you can download whatever you need, including any desired sections of the full technical manual. Typically, the wiring diagrams include complete pin-out descriptions, so if you can follow the diagram you can see which wire on the brake light switch to connect to. I did the Sienna without this.

[Pete Dumbleton]

I suggest calling Tekonsha in addition to anything else you may do. Free call.

They know what to do and what NOT to do on all the various vehicles. For example, connecting to the wrong brake switch wire on some Ford trucks can affect the ABS operation of the truck...

[Peter K]

I am getting here late, and perhaps you have got the problem done, but I just put the brake controller in my 2000 tacoma, and I ran three of the wires with all new primary wire, through a rubber plug in the firewall, and conected them directly to the battery (thats two done), and I ran the lead to the light hookup at the tailgate, the same, through the rubber plug, and along the frame to the back. now the brake switch wire is the only one left. I squeezed upside down, and did check the wires with a probe, and found the one needed, (I think on mine it was a green wire with a white stripe, but don't quote me) I then stripped some of the isulation back and spliced the new wire from the controller into that line, and wrapped it in electrical tape. I think the quick connectors would work, I just did not have any on hand. It worked great towing the new (to us) 5th wheel home 300 miles. no problems.