Smoke is a major contributer of contact resistance in vehicle. I would not be suprized if the vehicle was owned by a heavy smoker at one time. Also most switches should not be switched slowly. The contacts are made to slap closed witch wipes and cleans the contacting surface. Eric 86-VW4x4 vw4x4@fyi.net 72-240z Pittsburgh, PA USA 1936-Chrysler
On Sat, 23 Oct 1999, David Beierl wrote: > At 13:05 10/23/99 , Per Lindgren wrote: > >I dissected the old switch, and it was melted solid. I don't know what caused > >this, but the fan ran much better with the new switch than it did with the old > >switch. If another meltdown happens, I guess I will have to investigate > >further. > > I know! I know! The switch is made (thank you VW) of thermoplastic, and > carries 12 amps. When it gets a bit of contact resistance the contacts > heat up, the plastic gets soft, the movable contact presses the fixed > contact down into the soft plastic -- voila, it has just built itself a > little playpen. The contact pressure is less, the resistance is more, the > contact gets hotter yet... > > I *love* relays...my switch on high speed is now supplying all of 100 ma or > so to power a relay that feeds the fan from a dedicated circuit. At lower > speeds it has no trouble driving the fan itself. > > david > David Beierl - Providence, RI > http://pws.prserv.net/synergy/Vanagon.htm > '84 Westy "Dutiful Passage" > '85 GL "Poor Relation" > |
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