U.F.O (Unknown Fuse Observed)

Hey everyone,

I have somewhat of an interesting situation that I am looking for input on. I bought my 2017 SR5 Tacoma a year ago, and at the time I purchased the backup cam was not working.

During my initial troubleshooting, I thought that maybe there was a blown fuse (I have since learned there is no fuse for the tailgate cam), so I checked the interior fuse box. In doing so, I ran across a fuse that’s not within the fuse box. I disconnected the fuse to see what it controlled, which I have come to learn is the remote locking system.

Here’s the issue though, when I go to reinsert the fuse, it triggers the horn to blow and will not cut out until I pull the fuse out. I disconnected the battery terminal, waited 10 min for a full reset, inserted the fuse, and reconnected the battery terminal, and as soon as I reconnected, the horn started sounding yet again….

I bought the truck used from the Toyota dealership, and I was under the impression it was fully stock, but my mysterious Fuse is telling me otherwise here.

I have no intentions of taking this to the dealer to solve so any advice that could be provided in hopes of resolving this would be greatly appreciated.

Please help, It’s been 3 days and my neighbors are fed up with the horn! Jk, Thanks in advance!

 

Take the truck far-far-away and put the fuse in and when it starts to honk get in there and start it up.
Or do the remote lock thing.
Or just let it honk for a while and perhaps turn off by itself.

 

Pics of the fuse?

Sounds like it feeds some kind of alarm system, when you put the fuse back in it thinks you're stealing the truck. You need to cycle the door locks with the fob or the drivers outside lock with the key. That will tell it the owner is trying to get in instead of a car thief

 

maybe look for recommendations on local alarm and boom boom stereo shops, to see if they can dissect and fix?
Or, if you are feeling froggy, go under the dash in the steering wheel area and see if you can locate aftermarket wiring and/or black box to get a model number and more info.

 

pictures would definitely help here

 

My bets are that you are setting off the alarm system and simply need to notify the truck that you have a key.

I’ve never set of the alarm on my taco, but I did a least once in my Subaru by, if I remember right, locking the door with the key fob and then unlocking it with the key (or vice versa). The solution was to put the key in the ignition and turn it 3 times or something like that. It was a long time ago.

 

Thanks for the input here guys. I’m going to try everyone’s suggestions tomorrow morning and will let you know what the result is. Was raining tonight and I live within city limits so not a good night to test such items lol.

 

Hey all, updating with some pictures. The first picture is the fuse that I am trying to identify . The second is the harness that it goes into, and the 3rd and the wires that seem to be running from the steering wheel area (blue, white, yellow)…. Maybe this is a aftermarket remote start ?

 

looks aftermarket for sure!

 

Unplug the horn while you figure it out.

The lights probably flash at the same time, or use a test light in place of the horn if you need to tell whether it's honking on it's own.

 

that's an aftermarket fuse holder, and the module is also definitely aftermarket. would need to get model numbers off the module, and enter them into google to figure out what it is.

but it's likely some sort of aftermarket alarm system, that will now need to be removed from the truck...

 

Aftermarket alarm issue with suspect software, wiring, voltage etc

 

This worked, thanks for the advise!