Peter:
A relay is an electrically operated switch. In an automotive
application, the relay's contacts usually have more current carrying
capacity than the switch.. The other advantge is that they can be
remotely located, like the double relay in older L-Jetronic injection-
turns on the injection and the fuel pump from remote switch inputs in
the Air Flow Meter and the starter.
(Note: if your blower switch is burning out, you don't need a relay, you
need to oil your blower motor, or replace it, thereby reducing the
current needed to run the blower.)
Al Brase
87 Vanagon

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