Hello, I'm new to this forum, and originally came in search of an answer of how to fix a constant horn honk that appears in the middle of the night and particularly in cold weather. It is not the alarm, nor a bad relay or fuse, much to my dismay, I learned that the horn pad within the steering assembly was the culprit, shorting on typically during sudden depression/cold changes as a result of pressure from the airbag on thin wearing contacts within the pad and the repair costs for replacing the entire air bag assembly was upwards of $1200 depending on where you were quoted.
This killed my battery the first time it happened and tortured my neighbors while I slept. I brought the vehicle into my garage and couldn't replicate it, but the moment I left it outside a cold snap had me running out to bring it back in, to stop the horn, a simple tap/punch to the steering wheel seemed to get it to stop briefly but until you disconnect the short this will continue unpredictably. I brought it into the dealer on a warmer night and they couldn't replicate the issue but gladly would sell me a new assembly for about $1300 installed. Unacceptable on a car nearly 8 years old with constantly failing components, I've had to replace O2 sensors nearly every other year, and wasn't about to start doing the same with airbags that have a $1 switch broken in them.
I with the assistance of my husband attempted to diagnose and repair the assembly based on a random thread I found for some montero/pajero users outside the US that were able to repair the contacts. Much to my dismay in attempting the repair it simply isn't possible and research with airbag repair folks in the US state it is NOT a serviceable part. No reputable repair guy will even try it. There are solid grommets holding the airbag in and I stopped after removing the ignition plate on the assembly that we really couldn't go much further forward.
Unwilling to pay a lot for a fix, I did find a text writeup of how a guy disconnected the horn wire to the wheel and routed a new switch elsewhere on a 2001 Montero Limited. I did this as well, and have provided more detail and photos that I hope will help others. I believe the wire harness is the same on the 2001-2006 when speaking of USDM Monteros (not sport). Its a bit of a workaround but at least I have the horn back, I'm no longer worried about passing safety inspection in Virginia, and I didn't have to put an airbag on my Christmas wish list. I love my Montero in the snow and beach, but the random failing electrical stuff on the aging SUV is just annoying.
This fix cost me about $10 total Parts included:
- Black 18 Gauge Wire (had some in stock)
- Red 18 Gauge Wire (had some in stock)
- 2 - Wire Tap in Squeeze connectors - $2.19
- 2 - Quick Disconnects - $2.49
- 1 - Momentary Switch - $2.99
- Flat Screwdriver
- Phillips Screwdriver
- Drill Bit, 1/2" bit and a few smaller for pilot holes
- Soldering iron and solder to attach wires to the switch
- Electrical Pliers/Strippers to crimp wires to connectors
- Addons if you like: Electrical tape/heat shrink wrapping for any additional coverage
- Line toner to verify horn wire if it doesn't match what is pictured
Here are the overall steps
- Disconnect battery
- Locate near the clock spring (where the steering wheel actually turns) and disconnect factory horn wire inside steering wheel (red wire with blue stripes) (**The wire from here to the airbag/hornpad is what is shorting)
- Remove service panel beneath steering wheel and locate factory horn wire (green with black longitudinal stripe)
- Remove blank panel near illumination control
- Clamp and drill panel hole for new button
- Solder 1 black and 1 red 18 gauge wires to horn switch of equal length
- Add additional electrical tape/heat shrink wrap to each wire if preferred
- Install button to drilled panel (i just used a tight friction fit)
- Crimp male sides of quick releases to new horn button wires
- Tap Red wire to Factory Horn wire
- Tap Black wire to Factory ground located in illumination control (solid black wire)
- Crimp other female sides of quick release disconnects to tapped leads
- Secure Quick Release disconnects
- Reassemble all trim.
- Reconnect Battery.
Here are my Supporting Pictures:
Locating bad horn switch wire:
Locating Factory Harness Horn Wire:
Locating Panel for new horn button:
Where I grounded the switch:
How to drill the panel:
Drilled switch housing:
Momentary Switch Used:
Completed Horn switch panel:
New Line tap to horn wire: