dukenukemx

Just got this 07 Tahoe with 193,000 miles and just discovered the horn doesn't work. It does when I hit the horn button on the key fob and I took off one horn and tested it with a battery and it works. Checked the fuse and it's fine, but my tester doesn't show any power going to the fuse. I removed the airbag from the steering wheel and checked the horn button for corrosion and that seems fine. I gave the copper contacts a cleaning and put dielectric grease. Looked under the dash and didn't see any disconnected wires or anything odd.

I'm stuck and can't figure it out. Anyone have any ideas they can please share?

KChevy75

Was this previously a police vehicle?

Testing for power to the fuses in these vehicles will not always produce the results you expect. Some fuses don't get power until the computer sends the power to them after you tell it to perform a task. I'm not sure if the horn is one of them but it may be. With the airbag/horn contact cover off, did the horn function consistently when you manually pressed the contacts?

I'll see if I can find the horn wiring diagram in my repair manual.

KChevy75

Another things to try...Hold the horn down while turning the steering wheel all the way one direction then back all the way the other way. Basically, turn it lock to lock. Let us know if it honks at any point.

a55bruce

If the fob works the horn, you're half way there. The relay, fuse, and horns are OK. What's left is the horn switch, steering wheel coil, and the wiring connectors and harness.
Using your test meter you should have 12V on one side (TAN wire) of the horn switch (ground on the BLACK wire).
No 12V? Look for the TAN wire at the connector coming out of the steering column (hope there is just one).
If the wire color at the horn switch is NOT TAN, look for the same color wire.
Back-probe the connector to see if there's 12V on the TAN wire.
If you have 12V at the connector then you probably have a bad steering wheel coil assembly.
This is from my 2011 Tahoe, hopefully it's the same as your '07.

Shanna Horner

I left the sunroof open during a storm. The next day, while driving, the horn starting going off, and stopped after about a min.. Can't get the horn to work.. The changing the fuse, but no luck. I can't find where the horn relay is. My horn also beeps with the key fob.

repairman54

Horm beeps with the fob it's not the relay. There is only one horn relay. Water most likely got into the steering wheel connections or the clock spring coil connections.