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On 12 Nov 2002, at 11:06, Aaron Clow wrote: > On a number of occasions I've read you talking about > not putting more load on the ignition switch and to > instead add a relay... > > Could you explain this a little further for me? Any time you add extra accessories to your car, the power for those accessories is normally provided thru the ignition switch. While there are a few exceptions to this rule, this is usually done so that turning off the key automatically turns almost everything off, minimizing the chance that the battery will be run down accidentally overnight. The contacts in the switch are good for a lot of years of stock use, or a bit more, but as you add load (current) to the OE current that this switch must carry you eventually start to wear the contacts faster than normal. For a contemporary car this is not much of a problem because you can just go down to NAPA and buy another, but for our cars some years are getting quite hard to find, and expensive. The solution is to mount a relay which would be energized by a very small current thru the ignition switch, but which would switch a lot of the current that would have otherwise gone thru the ignition switch. A relay is just an electrically activated switch, where the control current is small, but the carrying capacity is large. It is activated by using the control current to operate an electromagnet, which pulls the "switch" contacts closed; when the electromagnet is turned off, there is a spring which pulls the "switch" contacts open again. The end result of this would be to prolong the life of the ignition switch. - Jim Adney jadney@vwtype3.org Madison, WI 53711-3054 USA ------------------------------------------------ To unsubscribe, E-mail to: <type3-off@vwtype3.org> For more help, see http://vwtype3.org/list/