Folks, Would appreciate help with towing tail light wiring assembly. I purchased wiring harness from 3rd party. Installed harness and 20 A fuse, but have no power to 4 pin towing light connector. Any tricks I may have missed? Fuse is fine, connector is fine. Having problem showing connectivity across fuse connections. Wondering whether a switch or relay is missing....

Would really hate to splice in the wiring.

Thanks.

 

Cant comment much without knowing what module you got.

You need wiring harness adapter(s) and a module. The one from Lexus consists of two arms of harness that go up to the left and right tail bulb assembly and one that leads to the trailor hitch. The module gets is power form the acessory plug in the back.

The module is needed to isolate the trialor from drawing current from the tail lights. This prevents tail-light failure bulb in the dash from lighting up.

Note: Depending on which year/model you have the wiring harness can be different .. ie Lexus came up with models termed as "tow ready etc". My description above is for 99 RX without tow ready.

Salim

 

I don't have any first-hand knowledge, but since you have apparently checked for continuity, how about checking for the expected voltages, before and after the fuses. I'm guessing you have turn signal voltage, left and right, stop light voltage, and tail light voltage?

 

Thanks for the suggestions. I have the 2003 RX300 (made in 12/02). I did some more wiring checks (fuse post was getting power, wiring harness continuity, but no power at tow wiring assembly plug) and found that a module is indeed missing. It is in the spare tire housing (wasn't obvious initially).

Salimshaw was right on the money... So, it's off to Lexus for the module...

Hope this takes care of issues.

Again, thanks for the comments / suggestions.