In the past Casper's Electronics made a flow detect kit that Intense Racing sold. Awesome product that gave you the driver the needed information if the pump ever quit pumping. There could be detrimental impacts if your car is tuned to the limit for power and the intercooler pump quits. I was lucky enough to have a buddy hand me one when I was about to install an intercooler on my car. Meanwhile I checked into these and they are no longer made/sold by Caspers. In mentioning these to a couple buddies, we came up with suppliers of the parts and the how to info.
Parts needed:
Flotect switch, aka elbow with flow switch in it. Base the switch to buy off the GPM of your pump.
Series V12 - FLOTECT® Flow Switch - Dwyer Instruments
1 Relay with 5 pins Same as any underhood. Junkyards are full of them. 8-)
1 Red LED Radio Shack
Red LED with Holder - RadioShack.com
1 Green LED Radio Shack
Green LED with Holder - RadioShack.com
Wire Again a junkyard can be your low cost friend.
Wiring of parts:
Chassis ground to one side of flow detect elbow
Other wire of flow detect is connected to pin 86 of relay
Igition power is connected to pin 85 of relay and both LED power leads.
Chassis ground connect to pin 30 of relay
Connect the negative (ground) side of the red LED to pin 87a of the relay
Connect the negative (ground) side of the green LED to pin 87 of the relay.
What you are doing is putting power to the LED's when the ignition is on and swapping the ground from red to green LED's via the relay. When the flow detect doesn't ground the relay, you default the red LED on. When flow is present, the flow detect grounds the relay which connects ground to the green LED.