Horn Problem

[ExCaptain]

I was wondering if anyone else is having trouble with their horn on their TB. Mine is a brand new 2004 (3000 miles) and my horn stopped working. Before this truck, I had a 2002 TB that had the EXACT SAME PROBLEM!!! As a matter of fact I turned it in with no horn and never told them! Anyway, I remember reading on here that someone else had a problem with it where it would not work going faster than 25mph. I tried this today and sure enough the same thing for me. The horn will not work when I first start up the truck. I will then drive to the first stop sign on my block. AFTER I apply the brake, the horn will work normal until I reach a speed of 25-30 mph. Then NOTHING!!!! It will be dead for the rest of my trip. Sometimes I might get one honk every so often but basically nothing. Is there something I could do before leaving it for repair. The dealer by me has the same menu for all repairs. Drop it off and wait 3 days!! I hope it is something that maybe I could try before going this route. Thanks in advance for any help. Happy holidays to all!

[GMMerlin]

The horn circuit on this truck is a fairly simple circuit.
The horn is controled by a relay which uses the horn switch or the BCM to ground the relay and apply 12v to the horn.
Haven't seen many problems with this..matter of fact I have only had one other and it was a bad relay.

As far as having to wait 3 days for a repair...wish my shop was that busy

[ExCaptain]

GMMerlin,
Thanks for the reply, Could I ask a few quick questions? The horn relay that you mentioned. Is this an item that I can replace myself? Where is the horn relay located? I was hoping I could replace it myself to save mostly time since I really can't leave my TB for repair right now I really need it. Also, is there any connection to the horn operation with the computer that controls just about everything else on this truck??? Thanks again for the reply and any answers you could give me.

P.S.: as a footnote, today while driving it I got cut off and instinctively I used the horn AND IT WORKED!!!! Also right after that I got on a parkway and while traveling about 60 mph it still worked. But after I exited the parkway and traveled the side streets to my house I checked again and it did NOT work! What gives?????

[Jethro]

I had a problem with mine and the dealer fixed it.

[GMMerlin]

If I remember right, the horn relay is located in the underhood electrical center..there is a label that will identify the relay

[ExCaptain]

Thank you very much, I will check it tomorrow and hopefully fix this problem. Happy Holidays GMMerlin!

[ExCaptain]

I have replaced the horn relay and it did not solve the problem. Is there anything else I can do to fix this problem before bringing it in for service? I really don't want to tie it up there for days, I can't be without a vehicle. Thanks for any help. Happy New Year!!

[GMMerlin]

Pretty much the horn contact grounds the coil which supplies power thru the relay to the horn.
Does the relay click when you depress the horn pad?

[ExCaptain]

Thank you very much for the reply, I will check that. Thanks again GMMerlin.

[RebeccaLee]

I have a 2003 Trailblazer LT & have had problems with the horn working/not working. thanks for the info on the relay switch. I have an appointment for service on it next week & will now know what to suggest in case the horn happens to work when they try it!

[Glo1029]

Originally Posted by RebeccaLee

I have a 2003 Trailblazer LT & have had problems with the horn working/not working. thanks for the info on the relay switch. I have an appointment for service on it next week & will now know what to suggest in case the horn happens to work when they try it!

I just bought a 2002 Trailblazer LT. My horn isn't working..more like it works when it wants to. Was the relay the problem??? If not, what was the problem?? Has anyone else had theirs fixed??