You might try temping in some wiring with an amp meter (jump the existing relay with the meter) to get an idea of the top motor current draw. Most relays have 10A contacts, but it would be nice to know for sure on the one you choose.
Thanks for the replies. I ran through my wiring diagram and found that theres no "relay" , but a circuit breaker inline for overloads. The hot runs off of the horn relay terminal to the top switch. I dont have a switch, it was missing along with the switch harnes that connects to the lead that goes to the pump motor. I noticed at a local parts store that they have replacement power window switches that are simular to what I need. So my question now is would one of those work for my application?
I highly recommend a relay. Just about everything on a car today that is over 8 amps is relayed to bring full voltage and high current to the powered device.
There is an automotive relay line available from Newark Electronics (www.newark.com) that will handle 40 amps and even 70 amps. I use the 70s for everything from cooling fans to windows and trunk operator in street rods.
Pulling current thru switches has a big disadvantage of voltage drops and so forth.
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