Fuel pump relay


10 Year Member
Feb 27, 2004
Ludlow, MA
Okay, so i'm not sure if i have this right...this is for my aeromotive pump

but here's what i have so far.


87 is going to the pump

86 is grounded

30 is going to the breaker, then breaker to the battery

85 no idea. what color wire does this go to from the stock harness?

this is really driving me nuts...not having the car makes it even worse because i can't remember what wire i hooked up 85 to:shrug:
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85 would be the positive relay coil. In stock form it's VPWR (if you unplug your stock relay and probe the terminals, it's the one that is key-on hot but off with the key off). Check your wiring diagrams for the correct color wire (per this diagram it's the red wire at the FP relay).
is it a red/black wire? i think that's the one i had in there....

I don't have a 91 so I cant say firsthand. Per the diagram it's just red. I don't see red/blk.
Pink/blk would be a wire with constant power, and not a wise choice.
Yep, the rest of it sounded fine. You could have probably even reused the OEM control side of the factory FP relay wiring for your new relay, but your method is just as good.

All that happens is that when 86 sees ground and 85 sees 12 volts, 30 connects to 87. Simple.

Good luck.
is that the wire that also primes the pump for a few seconds and then grounds it back out?

Neither the control wire nor the FP circuit ground out in order to deactivate the FP. The VPWR wire simply supplies 12 volts to most all the EEC systems when the key is on or cranking.

The wire that controls the prime-out with the fuel pump is another one. It grounds the FP relay's coil.