Recommended Powered 4-Pole Trailer Wiring Harness for 2004 Toyota Tacoma

Question:

Hello, I would like to know what parts or universal kit I would need to setup a 4 way flat or 7 way towing wiring harness. My goal is to have the circuit run directly to the battery with a fuse so it is not linked into the vehicle electrical system. I purchased a plug and play kit that was wired through the rear tailights but this setp went bad and it blew two of the vehicle fuses. Love the convenience of the plug n play but dont like that it can mess up the vehicle electrics and when the fuses blew in the truck I lost dashlights, rear tail lights and running lights. The vehicle is a 2004 Toyota Tacoma double cab. Thanks for any product recommendations.

asked by: Robert M

Expert Reply:

All of the custom 4-pole wiring harness kits made for your 2004 Toyota Tacoma are the passive type that plug in at your taillights without a direct battery connection, like # 118379 that you purchased last year - thank you. You can install a universal powered harness that has that 12V battery connection but this will be a hardwired installation, not a plug-n-play.

The ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit # 119250KIT includes the powered converter and a complete installation kit. This 4-pole harness can deliver substantially higher maximum current output than the other unit, up to 4.2-amps per stop/turn circuit and up to 7.5-amps for the taillights, nearly double that of the other harness you tried.

I mention this since it is possible that your fuses blowing could have been a result of the trailer pulling too much current for it. In this event you should be fine with the higher-current-capacity kit.

Another possibility is a short somewhere within the trailer wiring. You will want to test the trailer for proper operation by using a battery to apply power direct to each trailer light circuit one at a time. Do this with the trailer disconnected from the vehicle. If there is a short in the trailer, which could be an intermittent problem, you'll want to correct this before installing the new harness to protect it from suffering the same fate.

If you wish to convert the 4-pole flat connector to an RV-style 7-way you can at any time add the # ETBC7 kit, which includes all of the parts needed to install a 7-way with all lighting circuits as well as trailer brake power and trailer 12V power circuits.

Two helpful articles on trailer wiring are linked for you.