2013 Tacoma Tail-light Issue

Good day folks, I have a 2013 Tacoma that has a problem with the tail-lights. They work perfectly OK during the day (brake/turn signal) but when I switch the headlights on at night the 10amp fuse blows and the tail-lights are out. The headlights however are still working at this point! I am leaning towards it being the headlight switch possibly but wonder if anyone else has ever had this issue and found the problem!
Thanks!

 

Check the wires at the rear light and under the bumper. Most likely a wire contacting ground in that area.

 

Almost certainly not the switch, is the radio stock?
I'll post up the wiring diagram when I get time but you have a short somewhere.

 

10A fuse also handles interior dash illumination...

 

Thank You for the replies, the radio is stock! I will check the wiring by the lamps and the bumber as stated and then let you know what I found!

 

Sounds like in the taillight running lights that come on when headlights do look for a short there. Start by pulling the taillight housing out and inspect both sockets/bulbs and follow wires down.
Also if you have the tow package could be in the 7 pin socket and/or wiring and it has a big bundle tucked up in back and a big connector. Have you hit that 7 pin socket as its low. Again the running light circuit.

 

That is incorrect.
The towing tail has its own fuse and relay.

 

Found the problem, the trailer harness adapter appears to be the culprit! Checked the wiring and there is no apparent damage anywhere to be found. I disconnected the adapter's ground wire and the problem went away. Thanks for the help folks, much appreciated!

 

Pic?

 

Sorry, I didn't take any. Where I live the black flies are out so when working outside at present, I tend to get what is needed done and then get back inside! The light 3- 2 adapter though appears aftermarket although all the connections are with factory style plugs. Just goint to order a universal 3 - 2 adapter.

 

So the connection of this added towing combiner was the issue?

 

Yes, As soon as I disconnected the ground wire fron the unit, everything started to work properly. Not sure what type of adapter it is but I'm guessing it is the diode type. Opto-isolator types tend to fail open. I'm going to splice the new adapter in by solderng the wires and using some heat shrink tubing to protect them. The short was in the running light cct.

 

Your Taco should have a pigtail for a 4 wire connector behind the driver's kick panel. It's what they provided when the Taco wasn't assembled as a "full" towing version. It requires a mating harness and a tow converter.

Long length from Driver's kick panel to driver's side cab floor (comes with grommet), follows vehicle harness to rear bumper. Short harness secures to bumper.

 

This (above) is a good suggestion to check. I have a 7-pin to 4-pin connector/converter with small led tel-tale lamps for each function. They work even when it's plugged into the truck socket and there's no trailer connected. It proved the hitch wiring good when I wasn't getting tail-lamps or turn signals on one side. (running lamps good)

It turned out to be the connector on the trailer. I suspected it was the tail-lamp unit in and was ready to swap it out first. Saved me time and money. It also immediately ruled out the switch.

 

That harness is $132+ on Amazon. The adapter I ordered is only $30. I will splice it in while cuyting out the existing module.

 

You could assemble the harness much cheaper. Just need to purchase the towing converter and fuse.

But you keep re-using that oxidized aftermarket adapter...

 

The present adapter is fried. There's an internal short to ground. I'm just replacing the unit with another aftermarket universal unit.