Auto Start and Horn

[sharonvrla]

After having my 2000 Tahoe for a few months, I started messing around a bit to figure out why my horn doesn't work. I discovered the relay and fuse were removed. I replaced them. Upon starting my truck afterwards, the horn went off. Wouldn't stop until I pulled the relay. I still have no horn. I consider that a safety issue. Any thoughts on getting my horn to work properly?

 

[Bkihum]

After having my 2000 Tahoe for a few months, I started messing around a bit to figure out why my horn doesn't work. I discovered the relay and fuse were removed. I replaced them. Upon starting my truck afterwards, the horn went off. Wouldn't stop until I pulled the relay. I still have no horn. I consider that a safety issue. Any thoughts on getting my horn to work properly?

Change the relay

 

[sharonvrla]

Change the relay

Hi. Yes, I did that. If the relay is in place, the horn wont stop. (New relay)

 

[PPV_2018]

have you confirmed that it is the correct amperage rating on the new fuse and relay that you put in?


Hopefully not a clockspring issue. Does the horn pad on the steering wheel push in when you press on it?

 

[sharonvrla]

have you confirmed that it is the correct amperage rating on the new fuse and relay that you put in?


Hopefully not a clockspring issue. Does the horn pad on the steering wheel push in when you press on it?

Hi, yes the rating is correct on both and the steering wheel does push in when I press on it.

 

[Fless]

Two door or four door?

Here's a link to the wiring diagram; be sure to check the links at the very top to make sure it's the correct one for your SUV.

Horn Diagrams — 2000 Chevrolet K Tahoe 4WD V8-5.3L VIN T Service Manual | Operation CHARM

Detailed repair manual for the 2000 Chevrolet K Tahoe 4WD V8-5.3L VIN T.

charm.li

According to the diagram (and if it's the correct one for yours), the horn switch grounds the circuit to pin 86 of the relay. This is a very common way to activate the horn circuit. Check that relay pin socket to see if it's grounded full time (it should not be) and trace back if it is. The intended grounding point ("horn switch") is underneath the airbag in the steering wheel.

 

[Doubeleive]

After having my 2000 Tahoe for a few months, I started messing around a bit to figure out why my horn doesn't work. I discovered the relay and fuse were removed. I replaced them. Upon starting my truck afterwards, the horn went off. Wouldn't stop until I pulled the relay. I still have no horn. I consider that a safety issue. Any thoughts on getting my horn to work properly?

I would just pull the airbag off and inspect the horn contacts, verify the contacts are working as designed and go from there.

 

[Fless]

I would just pull the airbag off and inspect the horn contacts, verify the contacts are working as designed and go from there.

^^^ THIS. Pull the airbag off and disable the horn switch where it grounds. Replace the horn relay to see if it's still passing current. If it is, you'll know that it's not the horn switch, but in the wiring between the steering wheel and the horn relay control.

Does this have an aftermarket security or auto start system? If so, that's could be the cause.

 

[sharonvrla]

I would just pull the airbag off and inspect the horn contacts, verify the contacts are working as designed and go from there.

Could...but I know the horn works fine. The press test is fine as well. Its just that when the relay and fuse are in place is when all the demon pigs fly.

 

[Fless]

But if the horn connection is working incorrectly (being "always grounded") the horn's relay will be energized. Don't think that just because the "press test" lets you push it and it returns fool you into thinking that all is well there. It might be, but you won't know until it's properly diagnosed.

Test the relay contact for #86 to see if it's grounded -- my money is on that fault, whatever it's caused by. If it is grounded, then the horn circuit is being grounded when it shouldn't; could be the horn switch or a short to ground in the control circuit for the relay. Not much else can cause that.