Horn Issues
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Joined: Jan 2008
Posts: 42
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From: OH
Horn Issues
When I press and hold the center section of the steering wheel of my 2005 Lexus ES 330 sedan, the horn does not sound. But If I press and hold the lock button on my master key, the horn will eventually sound - so I know the horn itself has not failed.
Both the horn fuse and relay have been tested with a multimeter and by substitution, and both appear to be good. I've also replaced the clock spring, which has been noted to be a cause of horn failure. Have I missed anything obvious so far?
I'm really not looking forward to getting into the wiring but that looks like my next step. Does anyone have a link to the horn wiring for this year and model? TIA for any suggestions.
Steve in Ohio
Both the horn fuse and relay have been tested with a multimeter and by substitution, and both appear to be good. I've also replaced the clock spring, which has been noted to be a cause of horn failure. Have I missed anything obvious so far?
I'm really not looking forward to getting into the wiring but that looks like my next step. Does anyone have a link to the horn wiring for this year and model? TIA for any suggestions.
Steve in Ohio
Lead Lap
Joined: Nov 2019
Posts: 3,693
Likes: 1,102
From: Michigan
Hello,
Those cars are equipped with not 1, but 3 separate Horns, two on the Front of the Car, and the Third one being buried deep in the pits of the Engine Bay on the Driver's Side (that is if the Parts Catalogue is to be trusted) to make it as difficult to access from the outside as possible, which, as you can imagine, has an express purpose of being used for the Alarm System, as it's a well known exploit to either disconnect, or literally fill the Horns full of Spray Foam to prevent them from sounding the alarm.
Either way, start by Disconnecting either of the Horns on the Front of the Car, then use a Test Light to see if you have Voltage coming to said Horns when the Horn Button is pressed down. If there is no Voltage on the Horns, move on to the HORN Relay and 10A HORN Fuse.
Hope this helps and best of luck!
Those cars are equipped with not 1, but 3 separate Horns, two on the Front of the Car, and the Third one being buried deep in the pits of the Engine Bay on the Driver's Side (that is if the Parts Catalogue is to be trusted) to make it as difficult to access from the outside as possible, which, as you can imagine, has an express purpose of being used for the Alarm System, as it's a well known exploit to either disconnect, or literally fill the Horns full of Spray Foam to prevent them from sounding the alarm.
Either way, start by Disconnecting either of the Horns on the Front of the Car, then use a Test Light to see if you have Voltage coming to said Horns when the Horn Button is pressed down. If there is no Voltage on the Horns, move on to the HORN Relay and 10A HORN Fuse.
Hope this helps and best of luck!
Lead Lap
Joined: Nov 2019
Posts: 3,693
Likes: 1,102
From: Michigan
Hope this helps and best of luck!
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ShaunaLm
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