Horn issues (1 Viewer)

[sseaman]

I recently noticed that my horn doesn't always work, after some troubleshooting I found it is related to the telescopic column. According to the service history there was a burnt motor and worm gear repair prior to my purchase by a few thousand miles so I am wondering if there is possibly a short or loose connection. When it doesn't work I can move the column in and out then it will work until the next time the column moves which is of course when you remove the key. Any thoughts on what to check and how difficult is it to remove the column cover and trim?

 

[sseaman]

Bump for some thoughts on what to look at

 

[PADDO]

With intermittent operation like this you'd expect to find a loose connector or chaffed wire. Removing the steering column clam shell is very simple, check out some of the steering column tilt/telescope motor repair threads. You could always disable the column telescoping and/or lay off the horn blowing

 

[drjman]

My horn only works with a little dance and some luck. I'm going to open it up tonight and take some pictures. I'll let you know how it goes.

 

[sseaman]

Thanks, let me know what you find. I don't use the horn that often but it is a good safety feature to have. I have the cable on the way to check the AHC pressures and possibly disable the auto tilt/telescope option.

 

[drjman]

I went through and checked everything on my horn and magically it started working again!

Here are the steps I went through.

1. Checked the 10a fuse (good)
2. Pulled the relay and checked the connections, opened it up and everything looked brand new.
3. I removed the two side panels of the steering wheel with a small flat head screwdriver. Unscrewed the Torx bolt on both sides and popped the horn/airbag cover.

The white plug (bottom middle) is a single wire for the horn to connect to the rocker activators. (This is incorrect)

I left the yellow airbag wire plugged in. That thing made me nervous (I had the battery negative unhooked).

4. I plugged the white plug back in and started testing voltage in all the hot spots. All came back with 12v. So everything was active!?

Here are the locations.
Black Arrow: Grounding point
Top red arrow: Pin 6 (horn+) on the harness
Other red arrows: The four bolts on both left and right rockers.

5. With everything testing out ok, I plugged the battery back in and started putting the steering wheel back to together. All of a sudden, it honked! I got it all put back together and it would honk every try in all spots. There must have been a loose connection or something needed to be reseated. I basically checked, unplugged and plugged back in every component of the horn system.

Like others have said on various threads here, the horn is the most basic circuit in the car. If the relay, fuse are ok, make sure to test continuity and look for live wires with a volt meter.

 

[maxse01]

Great write up, thank you!

Both my 100's have this problem. Seems the more I use it, the more consistent it is.

 

[sseaman]

I worked on my horn issue this weekend, started with removing the column trim and making sure all the connectors were tight. After moving the column in and out and up and down and was not able to notice any visible issue the horn started working. Via Techstream I disable the auto tilt and telescope option and will keep an eye on how long it continues before not working again.

Thanks for the pics, removing the airbag and checking those connections was going to be the next step.

 

[NJNeal]

Isn't it possible this is potentially a clock spring or spiral spring short? Don't the wires for the horn run through the spiral spring?

 

[dwh13]

I know I'm bringing an old thread back from the dead, but I'm having no luck tracing my inop horn on my 03 LX. Here's what I've done:

1. Pulled airbag and checked contacts - everything visually appears ok
2. Checked for power at horns with test light - no power to horns when activated
3. Activating the panic button activates the horns, so they are still operational
4. No clicking from the horn relay

Any ideas?

 

[Ayune]

I know I'm bringing an old thread back from the dead, but I'm having no luck tracing my inop horn on my 03 LX. Here's what I've done:

1. Pulled airbag and checked contacts - everything visually appears ok
2. Checked for power at horns with test light - no power to horns when activated
3. Activating the panic button activates the horns, so they are still operational
4. No clicking from the horn relay

Any ideas?

According to the '04 wiring diagram, the horn relay can be activated (coil grounded) by the Theft Deterrent ECU or the horn button. The fact that the ECU can activate the relay means that the relay and your horns are still good. So the disconnection is between the steering wheel and the horn relay. Check for continuity through clock spring and/or pinched/broken wires through your steering column.

 

[dwh13]

According to the '04 wiring diagram, the horn relay can be activated (coil grounded) by the Theft Deterrent ECU or the horn button. The fact that the ECU can activate the relay means that the relay and your horns are still good. So the disconnection is between the steering wheel and the horn relay. Check for continuity through clock spring and/or pinched/broken wires through your steering column.

That’s good to know, thank you! I’m getting pretty handy with the mechanical bits but I’m still new to testing electronics. Any tips on where and how to test continuity?

 

[Jdfern]

The horn on my 2003 LC stopped working, I jumped the gun and bought a new clock spring from Toyota. While waiting for the part to come I continued to research and troubleshoot. Mine turned out to be a lost ground to the steering wheel. I had continuity every where except the actual steering wheel, i used a jumper wire to get ground to the wheel and the horn works . I was unable to find what was causing the lost ground, so I ended up putting in a permanent bridge wire.
Horns work perfect again.
I hope Toyota will let me return the clock spring.

 

[dwh13]

That’s good to know, thank you! I’m getting pretty handy with the mechanical bits but I’m still new to testing electronics. Any tips on where and how to test continuity?

To add a solution, when I took it to a shop to have the front brakes replaced, I asked them to take a look at the horn. Turns out, it was missing a fuse! I swear I've checked that a handful of times, no idea why it was missing. But all was well after that!

 

[kickitrootdown]

The horn on my 2003 LC stopped working, I jumped the gun and bought a new clock spring from Toyota. While waiting for the part to come I continued to research and troubleshoot. Mine turned out to be a lost ground to the steering wheel. I had continuity every where except the actual steering wheel, i used a jumper wire to get ground to the wheel and the horn works . I was unable to find what was causing the lost ground, so I ended up putting in a permanent bridge wire.
Horns work perfect again.
I hope Toyota will let me return the clock spring.

Having a similar issue with my 1999 possibly. Horn works with the PANIC button, but not from the steering wheel. Fuse is too good. I've taken off the airbag and fiddled around with the wires, making sure the wires were still intact and something hadn't just come unplugged. Everything looked fine, no rubbing on the wires, all the connections were sound. The cruise control wiring plugs into the same connector and that works just fine, so maybe it is the ground. @Jdfern can you describe exactly what you did to revive your horn? I guess my inexperience is showing perhaps when I don't understand what you mean that the cause was a "lost ground to the steering wheel" and how/where you put in a permanent bridge wire.

 

[Jdfern]

Having a similar issue with my 1999 possibly. Horn works with the PANIC button, but not from the steering wheel. Fuse is too good. I've taken off the airbag and fiddled around with the wires, making sure the wires were still intact and something hadn't just come unplugged. Everything looked fine, no rubbing on the wires, all the connections were sound. The cruise control wiring plugs into the same connector and that works just fine, so maybe it is the ground. @Jdfern can you describe exactly what you did to revive your horn? I guess my inexperience is showing perhaps when I don't understand what you mean that the cause was a "lost ground to the steering wheel" and how/where you put in a permanent bridge wire.

After taking the cover off the steering wheel, I used a pair of alligator clips to connect the metal steering wheel to a good source of body ground. Then test the horn. If it works you have the same problem. You can also check for continuity from steering wheel to a good ground. To correct the issue I permanently connected a wire from the wheel to a good ground. I don’t have any pictures of the connection but I was able to use solderless connector eyelets on a wire and fasten the wire to existing screws. Test with the alligator clips first, you maybe dealing with a different problem.

 

[kickitrootdown]

After taking the cover off the steering wheel, I used a pair of alligator clips to connect the metal steering wheel to a good source of body ground. Then test the horn. If it works you have the same problem. You can also check for continuity from steering wheel to a good ground. To correct the issue I permanently connected a wire from the wheel to a good ground. I don’t have any pictures of the connection but I was able to use solderless connector eyelets on a wire and fasten the wire to existing screws. Test with the alligator clips first, you maybe dealing with a different problem.

Do you remember what the good ground was? Did you thread it through the steering column or find another route?

 

[Jdfern]

Do you remember what the good ground was? Did you thread it through the steering column or find another route?

All hidden inside the cover, I attached the wire to “good ground” on this bracket on the lower column, I selected that cause it had good ground and it already had a hole in it.

 

[Jdfern]

Just to be clear the connection near the steering wheel is on the base so it’s not ever moving with the wheel, the clock spring does that.

 

[kickitrootdown]

Just to be clear the connection near the steering wheel is on the base so it’s not ever moving with the wheel, the clock spring does that.

We'll give 'er a go - thanks a million!