Boy was I surprized.

I recharged my dead battery yesterday. And after setting all night off the charger. This morning at 9:00 the horns started blowing. Woke up the whole block. Had to remove neg battery term to stop. Man where I start to fix this. Remove fuse 11 and Relay R5 to kill the horn ?

 

Horn just started blowing nonstop, constant, no pattern?

Bigger question is, why?

Do you have an aftermarket alarm?

Tell us more. Not nearly enough info here to diagnose anything.

 

Horns were wide open. No aftermarket stuff on my truck. I have had problem with water getting into my underdash fuse box. It has a good used one in there . It has been ok for a few months. There was no water in the floor. I will pull the fuse box and see if there is more water in it. The intergradation relay is in the fuse box if it gets water things go nuts.

 

Did you fix the reason the 1st one shorted? It's not uncommon for the windshield to leak and fry the integration relay (aka 'fuse box')

Don't bother pulling the fuse. Just go to the front of the truck, lift the hood, locate the horns. The horns are wired with a positive wire only, which is daisy-chained from one to the other, and each is are grounded directly to the radiator support, IIRC. Pop off either the ground or the power wire, whichever you find.

But let us know what you did to fix the previous leak into the integration relay.

Another common source of constant horn blow is a bad clockspring. But given the history of water entry into the integration relay, and how more commonly we see water in the integration relay causing stupid issues, I'm less inclined to think it's the clockspring.

 

Oh and here are some pics of what we've seen a few times here with regard to water leaking into the dash, usually suspected from the windshield, but I can think of at least one way it could get there via A-pillar.

 

I used half a can of flex seal up in there last time i worked on it. Going to use the other half if I can see any leak. Think I am going to mod a fuse block and move the ing relay out of the fuse box and put in its own little box outside the block. I have a couple of spares. I will try to post a picture.

 

Do you live in a corrosive area, somewhere the roads get salted/treated due to snow and ice?

I hate to say it, but you may just want to consider a new windshield. Sealing from the inside only allows water to puddle outside, which rots metal even faster. You can also use baby powder to dust the area above, any water that gets in will leave voids in the baby powder so you can see where water is coming from.

While water can come in via the A-pillar, I'd still suspect side/lower windshield leakage, but ... who knows? A little farther down in that post you'll see a reply with pics from Professional Hand Model ("PHM") showing potential leak sources under the side windshield trim (link) which are one possible source. over there.

 

Just curious....three years ago you started a thread about a similar situation. Surprised no one responded but in any case what did you find if by chance it was related ?

2005 SR5 Parking lights stay on | Toyota Tundra Forum (tundras.com)