how would you guys reccomend wiring the water pump for an aftercooler setup. car is 98 cobra and the pump will be located next to the heat exchanger up front. i want the pump to run when the car runs...thanks!
Through a fuse and pump relay energized by pin 13 on the CCRM which is hot only on start/run. You could also use pin 5 which is for the fuel pump, which also is energized during start and run and a few seconds after key on. Looking at instructions for a Saleen intercooler install, they tap into the fuel pump line from the CCRM (pin 5).
The Terminators actually have a pin on the ECU that grounds the pump relay directly only when the engine is running.
It's an all in one sealed relay box with a big connector that has like 4-5 relays in it (efi main relay, fuel pump, fan, ac clutch, etc) and various power signals for key on, start/run, FP, etc.
To get any kind of automatic setup that turns the intercooler pump on only when the engine is running, you'll need to tap the wire going into pin 5 or pin 13 for hot while running (vs at all times or with key on). Just check with a meter (or relay spec sheet if you have it) that the relay you use has decent resistance in the windings and isn't pulling excessive current since you'd be connecting one of those hot pins to one of the ground pins through your own provided relay winding (may need a resister if your relay doesn't have enough). Just need a few mA to close the relay and that's it.
If you follow the lines from your AC compressor or fans it should lead you to it to the CCRM. It's in various places depending on the year, usually the passenger fender well or a bracket near the radiator, not sure where it is on a 98 Cobra.
And of course, verify everything yourself with a meter before you start splicing things by verifying voltage at those terminals with key off/on/run and make sure things are actually as you read them on the internet. I've personally never done this and don't know if there are any variations.