2005 Sienna trailer lights

[katekebo]

This is my first thread, so I apologize in advance for any mistakes.

I identified the following problem with my boat trailer lights. The trailer brake lights don't work when I brake. The car's brake light operate normally. The turn signals on the trailer work fine. My hitch and wire harness were installed by the dealer, and has been working correctly so far. The wire connection is the 4-wire type, with ground, one cable for rear light, and two cables for turn signals / brake lights.

Because the turn signals work fine, I know that the problem is not with the wiring or light bulbs. Also, because car's brake light work, the problem is not with the brake light switch or fuses.

Now, because the Sienna uses separate bulbs for turn and brake likghts, while the trailer uses the same bulb filament for brake and turn signal, there must be some kind of relay in the car that combines the current from brake and turn signals into a single wire that goes to the trailer. I suspect that either the relay or some fuse are broken.

Can anybody help me to troubleshoot the problem? Where is (are) the relay(s) that activates trailer lights located? Where is (are) the fuse(s)?

Any help will be greatly appreciated.

S. Bucki

[katekebo]

OK, a brief follow-up note. My problem is solved. It was a blown fuse (5 AMP). It took me a while to find the fuse because whoever installed the wire harness did a great job of hiding the fuse holders under a patch of foam.

[geneowens]

How much weight are you towing with your Sienna? I just bought a Jayco pop-up camper and have not weighed it but it should be 1400 to 1500 pounds. I'm wondering if I need some extra lift or if lift is even available for the 06 sienna??? Do you tow in 4 or D??