A thermostatic switch - same one that would switch your fan on - can run the relay that runs your pump. These just switch to GROUND.... so it's just making your relay "grounded" on the switch side. Run your heavy leads for your power supply --- and the positive (small wire) to ignition switch (+ when the car is running) and the negative to your thermostatic switch... and you're done. The ONE thermostatic switch can easily switch both relays (Fan and Pump). It's doing nothing but grounding out the relays (hardly any load).
If you're using a relay - make sure it's matched (amperage wise) to your pump. 30 amps should be fine but you'll have to see what your pump draws.
Your relay should be numbered
#30 is the positive (fused) from your power source...
#87 is the positive (fused) to your pump
#86 is the positive to your ignition
#85 is the NEGATIVE to your thermostatic switch
You pump should just be grounded to a good nearest possible point.
Make sure your power leads are capable of handling the load given the distance...
The #85 and #86 can be light duty since they will only carry very small amount of amperage. They're just switching the relay on or off.
Last edited by GregWeld; 04-07-2012 at 09:56 PM.
|