Which one of these three is my fuel pump relay?

[MIKe30]

Only getting 8v to my fuel pump. Want to jumper my fuel pump relay to see if that is the culprit. Not sure which one of the three relays on my s52 harness is the fuel pump relay, or which slots on it need to be jumped.


Figure it's one of the three relays attached to my harness near my fusebox. Two are seafoam green, one in the middle is purple. Any ideas?

Thanks guys.

[Adrian_Visser]

Look up the wire colors going to the fuel pump relayin the ETM. What year is the harness from?

[bejbis]

you could always pull each relay at a time and check voltage until you get 0 volts.

[Wh33lhop]

IIRC the one with the huge (relative) wires going to it is the main relay, the one with the striped red/white wire going to it is the fuel pump relay.

[MIKe30]

Look up the wire colors going to the fuel pump relayin the ETM. What year is the harness from?

harness if from a 96 m3

you could always pull each relay at a time and check voltage until you get 0 volts.

That wouldnt work since one of them is the dme. Pull the dme and you should get zero volts just the same.

IIRC the one with the huge (relative) wires going to it is the main relay, the one with the striped red/white wire going to it is the fuel pump relay.

Yea, there is one with 3 huge red wires and one tiny brown... figured that was the dme just looked like a bunch of power and a ground.

That left me with 2 buttt still clueless. Wouldn't know which of the 4 slots needing jumping either.

[flyboyx]

well, my engine came from a '00 mz3 and i also kept obd2. in my case, the fuel pump relay was in the body wiring harness. there were a lot of differences through the years. can you take a photo of your relays? that would make it easier for me to help you out.

[MIKe30]

well, my engine came from a '00 mz3 and i also kept obd2. in my case, the fuel pump relay was in the body wiring harness. there were a lot of differences through the years. can you take a photo of your relays? that would make it easier for me to help you out.

yea, I came across your thread when I was searching this. I think yours being a part of your body harness may be a mz coupe thing. Either way I'm going to look up part numbers and see if that identifies it. If it doesn't while i'm there I'll snap a pic with the berry.

Thanks.

[flyboyx]

yeah....i don't think the part number is going to help you out either. in the case of my car, all the the relays outside of the fuse box are identical. take a look at your etm. find out what color the corresponding wire is that runs through your c20 plug. look at the wires that feed your relays to find the one that matches. remove the relay and touch the contact at the c20 and the relay with your volt meter set in the ohm range to see if you have continuity. that would also be a good place to start to see if you 12v.

a relay is just a simple electrically operated switch. only 4 wires are required. there are two small wires that use a small amount of amperage to close the contacts and allow current to flow through the two large wires. one little wire will go to a small fuse in your fuse box. the other will go to ground. of the two large wires, one will also come from the fuse box with a larger fuse, the other will go to your fuel pump.

[MIKe30]

yeah....i don't think the part number is going to help you out either. in the case of my car, all the the relays outside of the fuse box are identical. take a look at your etm. find out what color the corresponding wire is that runs through your c20 plug. look at the wires that feed your relays to find the one that matches. remove the relay and touch the contact at the c20 and the relay with your volt meter set in the ohm range to see if you have continuity. that would also be a good place to start to see if you 12v.

a relay is just a simple electrically operated switch. only 4 wires are required. there are two small wires that use a small amount of amperage to close the contacts and allow current to flow through the two large wires. one little wire will go to a small fuse in your fuse box. the other will go to ground. of the two large wires, one will also come from the fuse box with a larger fuse, the other will go to your fuel pump.

I didnt get a chance to get to the garage yet. Appreciate the explanation, but I do understand how relays work, I use them all the time at work on fire alarms. SPST, DPDT, etc etc. I just dont know which relay is my fuel pump, and which slots need a jumper without an etm. Going to check in what literature I have. Probably should have started there instead of looking for the easy answer online.