View Full Version : HELP with fuel pump relay schematics

11-21-2009, 11:27 AM
I have a 4 prong fuel relay. i need to know which is on, and which is off so i can test with a multimeter. Any help?

11-21-2009, 01:46 PM
the one closest to the front of the car and the prong closest 2 the driver side i believe.

11-22-2009, 10:37 PM
If you look at the bottom of the relay, the pins should be numbered. The socket is also numbered. Pins 86 and 85 are the coil, 30 and 87 are the contact.
Pin 86 will put out 12V when the key is in run or start, pin 85 goes to the ECU, where the ECU decides whether or not to make the circuit work(CPS, main relay ok?).
When the ECU sees everything is ok, it allows the coil to activate, and the contact between pin 30 and 87 closes. Pin 30 is always 12V, Pin 87 provides power directly to the pump.

11-22-2009, 11:14 PM
Thank you for that information.

on another note, from your e30 part out. would you by chance have the door locking circut located beside driver side door. Would it be the same for my 89 325i?

11-23-2009, 09:45 AM
power locks control module? nope, but I am parting another IX over the winter and will have one in a couple months. Search around, I'm sure there are a lot available.