Intermittent horn
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Pole Position
Joined: Nov 2014
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From: CALIFORNIA
Intermittent horn
Pushing the horn button on 1999 LS400 did not produce an expected honking...
Not sure if humidity related but encountered a downpour hours before malfunction
However, tried the horn again the next day and it worked perfectly.
So it would appear there is an intermittent issue that merits attention.
Any members experience this issue?
How did you resolve it?... relay, wiring, connectors, actuator button contacts, grounding or ground wire?
Thanks.
Not sure if humidity related but encountered a downpour hours before malfunction
However, tried the horn again the next day and it worked perfectly.
So it would appear there is an intermittent issue that merits attention.
Any members experience this issue?
How did you resolve it?... relay, wiring, connectors, actuator button contacts, grounding or ground wire?
Thanks.
Thread Starter
Pole Position
Joined: Nov 2014
Posts: 3,254
Likes: 418
From: CALIFORNIA
I think it might be temperature related. Last winter when it was real cold my horn stopped working until the temperature raised back up some. Have you checked the connections by the hood latch?
Last edited by sha4000; Jul 20, 2016 at 06:29 AM. Reason: Spelling
CL Community Team
Joined: Aug 2011
Posts: 4,181
Likes: 1,010
From: Japan
Pushing the horn button on 1999 LS400 did not produce an expected honking...
Not sure if humidity related but encountered a downpour hours before malfunction
However, tried the horn again the next day and it worked perfectly.
So it would appear there is an intermittent issue that merits attention.
Any members experience this issue?
How did you resolve it?... relay, wiring, connectors, actuator button contacts, grounding or ground wire?
Thanks.
Not sure if humidity related but encountered a downpour hours before malfunction
However, tried the horn again the next day and it worked perfectly.
So it would appear there is an intermittent issue that merits attention.
Any members experience this issue?
How did you resolve it?... relay, wiring, connectors, actuator button contacts, grounding or ground wire?
Thanks.
CL Community Team
Joined: Aug 2011
Posts: 4,181
Likes: 1,010
From: Japan
Attached is from a JDM service manual but it may be possible for English speaking people to find out where's the horn relay and the pin assignments. The pin#1 is connected the switch at the steering, pin#2 to the horn relay fuse and pin#3 to horns.
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Thread Starter
Pole Position
Joined: Nov 2014
Posts: 3,254
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From: CALIFORNIA
Can you post a higher resulution image of the fusebox diagram. Thanks
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Pole Position
Joined: Nov 2014
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From: CALIFORNIA
The horn and it's mounting tab is painted, the radiator surround is painted, as are the tapped holes, and the fasteners are again painted(?) thread-forming screws with lock washer and captive flat washer.
The attached images clearly show a deficient grounding scenario.
I am beginning to think such grounding issues are systemic.
Painted horn mounting bracket side that mates with painted radiator shroud to ground.<br/><br/>Single wire connector
Radiator shroud tapped hole...painted at factory.
Horn bracket mounting fastener does not suggest optimal grounding between horn and body
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Pole Position
Joined: Nov 2014
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From: CALIFORNIA
The clock spring was functioning
The relay was working properly..
I observed
he horn would only work when the telescopic steering mechanism was adjusted all the way in...and both ends of the concentric shafts were abutting up against each other.
So I reasoned the lubricant was insulating the sliding components...
A supplementary grounding cable was fabricated using more flexible 14 gauge fine strand tin-plated marine wire with a #8 and 3/8" ring terminal.
This ground strap was connected at the existing ground strap (closest to driver)#8 screw hole and routed alongside the steering column harness with a loop the loop(permitting extension and retraction) to the steering column support bolt(right of column)
The loop was affixed with a single small cable tie where finger is holding wire loop in image.
Supplementary ground wire installed. Finger is where mini cable tie was affixed.
To better access this ground screw, slightly bend downward the steering column harness support bracket. I left the original ground wire in place and simply added another at this location
This is where the 3/8" lug was affixed to the body...wire barrel side up serves as a stop to prevent spinning of the terminal whien torquing nut... Horn works better than ever.
Thread Starter
Pole Position
Joined: Nov 2014
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From: CALIFORNIA
The normal (original) ground wire spans across the tilt joint pivot and ends before the sliding mechanism...so before adding a ground wire from that point to the body, continuity was inconsistent. Now the horn works.
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