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GM Bob
GM Bob, ASE Certified Technician
Category: Chevy
Satisfied Customers: 1063
Experience:  30 plus years. experience as GM technician, ASE Master Technician and GM Certified.
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Chevrolet Tahoe LS: dan, my 07 Tahoe LS horn just started to

Customer Question

dan, my 07 Tahoe LS horn just started to blow for no reason. I disconnected the batt until I found the fuse. hooked the batt back up and it started blowing erratically as even while the truck had a key in it. so I pulled the fuse. then I needed to get in the back of my truck and the back hatch will not release and open on its own when I hit the buttons on the inside I hear the mech working and it hums for a second as I manually open the hatch. is this all connected? and could the Relay be bad?
Submitted: 1 year ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 1 year ago.
Hello, I'm Cam.
Can I get your first name please?
Sorry to hear about this issue. Can you tell me if your hatch is the power lift or manual only?
Customer: replied 1 year ago.
My name is Wade.
power lift. but my main concern is the Horn issue. the horn will not stop I pulled the fuse and when I pulled the fuse is when I noticed the hatch issue. my wife was cleaning the truck she needed to get in the back of the truck to unhook car seats.
Expert:  GM Tech (Cam) replied 1 year ago.
Understood Wade. If the horn blows even with the fuse removed then that leaves an issue either with the relay/fuse block in the underhood or the wiring directly under that. The reason I say this is because the horn fuse is the last link between the fuse block and the horn. So you need to check the wiring under the fuse block. If you see no issue then its a fuse block. And that would also support your issue with the rear hatch.
Customer: replied 1 year ago.
No it doesn't blow with the fuse removed.... that's the only way I could get it to stop.
I ment I didn't notice the hatch issue until after I pulled the fuse. not sure f the fuse is linked to the hatch..
when I grab the handle I hear the mechanism moving but if I just pull it and let it do its autolift it locks it and I cant open it. I have to start the truck to reset it.
so every time I grab the hatch handle I have to pull it past the initial pull that triggers the Autolift. and manually lift it.
Expert:  GM Tech (Cam) replied 1 year ago.
OK, Do you have an aftermarket remote starter installed?
Anything around the steering column installed?
Customer: replied 1 year ago.
nothing like that. 2 key fobs that come with the truck. But and I tried to stop the horn as if it was the alarm and it did nothing. the truck is totally stock. nothing aftermarket.
Expert:  GM Tech (Cam) replied 1 year ago.
Ok, was the horn blowing solid or pulsing like when you use the car finder?
Customer: replied 1 year ago.
it was doing a little of both solid and erratic. mostly erratic though
Expert:  GM Tech (Cam) replied 1 year ago.
Do you have to be moving for this to happen? Anything you can think of that causes it? Changes it? Makes it worse?
sorry for the delay, having internet issues.
Customer: replied 1 year ago.
This happened with no key in the ignition. My wife was just cleaning the inside of the truck doors open and it started to beep then more eratic. Then it got worse so I leave the fuse out.
Expert:  GM Bob replied 1 year ago.
Hello my name is ***** ***** I can help.
With the fuse out truck starts runs ok?
Do you have any lights flashing?(park lights,headlamps)
The body control module controls the horn relay.
The horn relay is built in to the under hood fuse block.
Do you had a scan tool that can read body control data.
Need to see if the body control module is commanding on the relay?
If you have no lights flashing or security light
and it starts and runs. I would say the relay is stuck on.
Was anything cleaned under the hood with water?
Please get back with me
Thank you
Customer: replied 1 year ago.
Nothing was cleaned u Der the hood with water. Wife didn't even get to wash the outside. No I do not have have a scan tool. Truck runs fine nothing has changed With that. Parking lights running lights work fine With the fuse out. If i put the fuse back in it takes a couple min/seconds and it starts up again
Expert:  GM Bob replied 1 year ago.
Just to make sure you are removing #28 fuse in the under hood fuse block?
There is two styles of horn relays. Can you post you VIN#
Have you tried to tap the under hood fuse block with the palm of you hand? see if you can unstick the relay.
Thanks
Customer: replied 1 year ago.
Vin. 1GNFC13J27R303242
YES THE #28 fuse
and no I haven't tried to tap under the fuse block. I will try in the morning it is after 11pm here in new orleans s
Expert:  GM Bob replied 1 year ago.
The horn relay you have is built into the fuse block.
I looked closer at the schematic the horn pad in the steering goes also feeds the relay besides the BCM.
Try moving you steering wheel up and down see if the horn stops.
Do you have a multimeter or test light?
Not sure how far you want to get into this? Next step will be taking fuse block out and testing wires.
Thank you
Customer: replied 1 year ago.
I do not have a multimeter or test light at home. I do have one at work but won't be around until June 15th. As I am going in vacation tomorrow. This sucks as I'll have to leave my tahoe behind and take a rental. I do not want to drive it with out a horn On such long distance. Can we resume this after the 15th?
Expert:  GM Bob replied 1 year ago.
Yes that will be fine with me .
Just come back and post when your ready.
Have a safe trip.
Thank you
Customer: replied 1 year ago.
Not sure how this works but I know we are not finished. Looks like I was charged $33 and The $5 deposit? Thought the $33 came after I agree the service was worth that?
Expert:  GM Bob replied 1 year ago.
I'm not sure how they bill you.
The question may close after few days. But you can reopen it.
Customer: replied 1 year ago.
I had a little time last night to do a few things you asked. I knocked on the fuse block/relay box. I moved my steering wheel up and down. The horn doesn't blow well hasn't yet. When I click on my key fob the horn sounds when the alarm are is set. But now I have no horn on the steering wheel.
On another note I figured out the rear hatch as well. My dang kids clicked the switch by the sun roof that opens the hatch. It was set to the (O). Clicked it back to the picture of the hatch and it works just fine. So when I come back let's focus on this hornThanks
Expert:  GM Bob replied 1 year ago.
It sounds like a wire or horn contacts in the steering column.
If it was the relay you think it would have stuck on after using it.
Have safe trip
Thank you
Customer: replied 1 year ago.
do I need to pull the airbag to get to the contacts? just wondering? ill deal with it when I get back. but damn its going to stick on my mind! and bug me
Expert:  GM Bob replied 1 year ago.
It may just be a wire rubbed through and grounding out.
Air bag is not hard to take off.
Just enjoy your vacation. It all good
Thank you
Customer: replied 1 year ago.
GM Bob. I am back from vacation. can we continue the trouble shooting?
Expert:  GM Bob replied 1 year ago.
Hope you had good time.
I'm just leaving for work right now.
I have lunch at 12 noon central time.
We left off at the steering wheel pad my be sticking?
Customer: replied 1 year ago.
the last thing i did before left was.... "I knocked on the fuse block/relay box. I moved my steering wheel up and down. The horn doesn't blow well hasn't yet. When I click on my key fob the horn sounds when the alarm are is set. But now I have no horn on the steering wheel. "using the key fob i was not able to remote start before i left for vacation. And yesterday out of habbit i tried and it worked. so not sure if that was liinked to the issue or if that was the FOB issue!
Expert:  GM Bob replied 1 year ago.
Ok now the doesn't work with steering wheel.
Can you move the tilt up and down and push on the horn pad same time?
See if it get stuck on or even work.
Customer: replied 1 year ago.
ill do that at lunch if the wife is home with the truck!
Expert:  GM Bob replied 1 year ago.
Just keep me posted
Customer: replied 1 year ago.
Moving the steering wheel up and down and trying the horn at same time did not work.
Expert:  GM Bob replied 1 year ago.
Here the instruction how to remove the airbag.
https://www.dropbox.com/sh/3msjr3arb6x1ngs/AABeogynCslU2EO70lUS22jSa?dl=0
When removing or replacing an SIR component Disconnect the negative battery cable.
Need to check the horn contact switch
Disconnect the wire on the contact switch. If you touch it ground the horn should blow
Expert:  GM Bob replied 1 year ago.
Sorry I wanted you to do one more thing before you take it apart.
With engine running turn the steering wheel all the way to left and right.
While pushing on the horn.
Let me know
Customer: replied 1 year ago.
bob. sorry I have not had the chance to get my air bag off and check the horn Contact switch. I hope to do so this week! I have been on call for the last 3 weekends since back from vacation and it has rained all 3 weekends.
Expert:  GM Bob replied 1 year ago.
Thank for keeping me updated.
Just let me know if you need more help
Thank you
Customer: replied 1 year ago.
Ok I removed the air bag and pulled the switch out no corosion everything looked clean. I used a wire to ground out the contacts and still nothing. I also had someone once I out everything back together push th horn button. I can't hear the contact engage under the fuse box. Am I supposed to hear it engage?
Expert:  GM Bob replied 1 year ago.
The horn still works with the remote?
You had a single wire that was hooked to the contacts. Did you ground that wire?
You may need to go to the main connector at the base of the steering column.
Find the horn wire and ground it if it works than you may need coil assembly.
Here is the connector located and a link. All you need to do is back feed a ground to the tan wire. The horn should work.
Steering column harness to instrument panel harness left center of the I/P on the steering column behind the knee bolster near the body control module
https://www.dropbox.com/s/0eiu22yfap5xcb6/2007_Tahoe_C201.png?dl=0
Customer: replied 1 year ago.
yes it still works with the remote. I also tried to tie into one side of the fuse and ground the other side i didnt get anything that way either. which doesnt make since if it works with the remote?i took a single wire and touched the contacts and grounded it to the center nut on the steering wheel. I also tried to ground it to the ground wire that connects to the horn switch. I tried all 4 of the contacts. I also tried to ground it to one of my fender bolts.can you send me info on the Coil as well? and where to get one if need be?thanks
Customer: replied 1 year ago.
Can you give me a diagram of where that plug is located? Am I pulling the air bag back out and dealing with the plug behind it? Or is this further down the column? Am I removing the plastic around the column?Thanks
Expert:  GM Bob replied 1 year ago.
This is my best picture
https://www.dropbox.com/s/q1hqmy5k79wb1oi/2007_Tahoe_C201_veiw.png?dl=0
Customer: replied 1 year ago.
That looks like the one attached to the back of the staring wheel. I'll have to pull the airbag back our I guess? Its raining now I'll try tomorrow
Customer: replied 1 year ago.
What is the I/P?
Expert:  GM Bob replied 1 year ago.
I/p is instrument panel.
If you have this type the horn does not go through the coil assembly.
https://www.dropbox.com/s/2v3d86nevshxbxz/2007_Horn_contact.png?dl=0
With air bag off can you post a picture.
Customer: replied 1 year ago.
will do if it isn't raining when I knock off today!.... supposed to be long weekend and the boss might let us off early today so I might beat these late afternoon/evening showers!
Customer: replied 1 year ago.
Here is a photo from behind the contact. And from behind the steering wheel . I tried to ground from both points. Where the tan wires are at.
Expert:  GM Bob replied 1 year ago.
thanks that helps me.
The horn runs through the coil assembly.
The connector that comes out next to the air bag wires. That is for the horn and controls in the steering wheel.
If you look at the picture I posted last. Look for the wires that plug into the air bag coil. The yellow covered wires are air bag wires not horn. Disconnect the connector see if find a tan wire.
Customer: replied 1 year ago.
I did unPlug the long connector with the brown wire. I tried to ground it from the plug as well as after I unplugged it. Then I tried to follow that harness down the column under the dash I lost where it went as everything is wrapped together with everything else from the steering wheel. Where does it go once it gets threw the fire wall? My wife said when the horn was honking on its own (when the problems started) she smelled electrical burn once the neighbor got my hood open. And battery disconnected. New info that the wife left out. I will prob ohm from each contact to the plug. Then from that point to under the dash not sure how to go from under the dash threw the fire wall? Mayne attach a wire under the dash to one lead on my meter and my other lead where it goes into the fuse box under the hood? I am thinking it's between the fuse and the plug under dash?
Customer: replied 1 year ago.
Is the center nut on the steering wheel a good ground?
Expert:  GM Bob replied 1 year ago.
Some times it has plastic connection down the column. I would run a ground wire to test with.
I think the problem is in the column some where.
The same wire the BCM uses to work the horn with the remote.Connects to the same wire from the horn button.
Here is the schematic
https://www.dropbox.com/s/9pbart6loij1ncu/2007_Tahoe_horn_schematic.png?dl=0
Customer: replied 1 year ago.
I ran the ground to the door jam hinge and some of the bolts in the jam