Solenoids won't typically "fire" on their own--the spring prevents it. Typical failures are burned/broken windings (electrical failure), broken return spring or dirty/jamming (mechanical failures).

The switch is wonky.

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James Marriott
2003 Buick Regal
1983 300D (228k, frau Auto)
1996 Suburban K2500 (192k, 6.5 turbo diesel/4WD towmaster 10,000)
www.engineeringworks.biz
1987 300SDL junker 170k
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