Hi ya'll been trying figure out why my tail light fuse keeps blowing.

I have an automatic SR5 with 280k on it. And have checked the following:


- All bulbs on that fuse
- Wiring going into the hatch
- Tow hitch wiring was removed 2 years ago
- Fuse box wiring
- All wiring behind dash and gear selector
- License Plate and Tail Light wiring
- Tail Light Relay

I have read the Tail light fuse keeps blowing? thread a number of times that info is not helping fix this issue.

I'm really at a loss and for the first time in a long long time can not fix something myself and have to take it some where. Any input on something I may have missed would be greatly appreciated.

It first did it 2 months ago and then went a whole month with out it blowing. Some times it will last 10 mins or so but most of the time it blows instantly as soon as the parking lights are turned on.

Check inside the wire loom connected to the hatch.

Check the trailer wiring harness connector. It is probably rusted/shorted.

There is a sub harness on each tail light (bulbs to harness to gromet to interior connector). I had a issue with my right tail light that would blow fuses. I'd take a look there, unfortunately you do need to take both rear panels off to access the sub harness connectors.

You probably have a bare wire somewhere in this circuit. rubbed the insulation off and dead shorting to ground. Or a pinched wire where the insulation is broken shorting. That happened to be on the trailer hitch.

What happens when you disconnect the module for the hitch completely? Sometimes they can short internally too..

Time to start unplugging things and see when the fuse stops blowing. I'd start with the plug up in the ceiling near the hatch along with the each tail light. The gauge cluster is another possible culprit, though it can also be any of the interior backlight connections...

-Charlie

Just a friendly reminder as stated in the original post:

Tow hitch wiring was removed 2 years ago

This has been checked.

This has been checked

I will disconnect that and see thank you!

Good call! I will unplug the tail gate connector and see. I did check all of the interior back lights except for the cluster will also do that.

Hell yeah, thank you phattyduck!

I started by unplugging the tow hitch module and the fuse blew.

I then disconnect both the White and Gray connectors that go into the hatch. Boom fuse did not blow! (One trouble with diagnosing this has been that when the fuse first blew, it went a month with out blowing again.. Then was very random when it would blow) So I went for a quick spin and it held til I got back. I then plugged in the grey connector and the fuse blew - BINGO!

So I take it that it has to be the license plate light wires right? Pretty sure that is the only thing in the hatch on the tail light fuse? I don't have a helper right now so I don't know exactly what else the grey connector powers in the hatch.. But as long as I have taillights I really don't care about anything else for the time being.

Thank you all! Goes to show how multiple threads on the same topic can be beneficial. Is there anyway to merge threads or something like that?

I thought you may have just removed the trailer hitch wiring to the hitch itself and left the module in place... As lots of aftermarkets modules connect to the passenger side instead of drivers side. When the drivers side modules fail. We cant get replacement driver side unless used somewhere. :-(

Glad you found it. :-)

What year of 3rd gen are you working on? I didn't see it listed in this thread just its a sr5 v6

License plate lights are on that connector. The connectors name is BR1 dark gray, pin #9, top roof left. On my 2000 that wire is green in color. It then goes to connector BS1, pin #9 green, dark gray connector by rear hatch control box. Then goes to connector L1 (bulb receptacle) pin #2 green. The white/black wire at bulb is ground, which goes back through connector BS1 (pin 3) BR1 (pin 3) and grounds at left quarter panel inner (BH).

Hope this helped.

It's a 1996.