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Lead Driver
Joined: Sep 2007
Posts: 8,180
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From: Scio, OR
Mine does and I can explain why. It might be model year (or engine) specific.
There are 3 wires going through the clock spring for the cruise and horn and illumination functions. The switches, lights and horn are wired with resistors, so that pressing one of the buttons applies a specific resistance across 2 of the 3 wires. The PCM looks at the resistance across those circuits and knows what button you are pressing. It just happens that pressing the On and Coast buttons at the same time produce the same set of values that pressing the horn does. The PCM module can't tell the difference when it sees this so it activates the horn relay.
There are 3 wires going through the clock spring for the cruise and horn and illumination functions. The switches, lights and horn are wired with resistors, so that pressing one of the buttons applies a specific resistance across 2 of the 3 wires. The PCM looks at the resistance across those circuits and knows what button you are pressing. It just happens that pressing the On and Coast buttons at the same time produce the same set of values that pressing the horn does. The PCM module can't tell the difference when it sees this so it activates the horn relay.
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