Request for test of secondary air pump fuse

[igeak691]

I am in the process of trying to figure out where in the circuit my secondary air pump isn't working. There are two fuses for the secondary air pump. A 10a fuse and a 50a fuse. The 50a fuse is live even when the car is off. I'm wondering if anyone here can help me check if the 10a fuse is live when the car is off. I checked my relay and it works but I don't get a 12v signal to the pump's power connector when I first turn on the car, so I know the problem is upstream of this. And I've checked the 10a fuse and 50a fuse, both are in working condition.

[bcworkz]

According to the WDS the 10A fuse is switched with the ignition ("Terminal 15"). This is according to the signals section, for some reason that fuse doesn't show up in the power distribution diagram. I can't physically confirm this as my car doesn't have an air pump.

[igeak691]

Thank you.. that makes sense. Now I guess I have to trace the wiring to see where there is a break in the wiring.

[Dogmatic6]

Hi,

My secondary air pump wasn't working for around a year and I had the emmisions light on. My fuses and relay checked out fine.

An auto electrician removed my fuse box and cleaned the contacts which had furred up a little. This resolved the issue!!

something to keep in mind.

Cheers

[igeak691]

Thanks for the heads up.

Anyone know if the fuse goes before or after the relay? Any wiring diagrams around?

[bcworkz]

Relay is after fuse. You can use bmw-planet.com to access the WDS, the navigation requires Java which is either disabled or not available on some browsers, so you may need to do some configuration to get it working.

[igeak691]

Did some more diagnosis but didn't find the problem yet. The relay is clicking as it should when a 12v source is applied. There is continuity between leg 5 of the relay and the power connector so there's no break between the relay and engine compartment. There's continuity between leg 3 and the 50a fuse.

Does the secondary air pump turn on when the ignition is put into "on" or does the car need to actually be started? Once started, I should really only have a minute or so to check if the relay is getting signal power to it. Anything I'm missing?

[igeak691]

Here's a kicker..

When I took the relay out and started the car, it would only stay on until I let out the clutch (did all this in neutral). After the first start, the car would not even turn over. Then when I put the relay back in, everything normal. Can anyone explain why the car will die when the relay isn't in and the clutch gets released?

BMW electronics is a real treat...

Edit:

Figured out today that I took the fuel pump relay out last time instead of the air pump relay

[igeak691]

I think I found a flaw here.. the power connector positive and negative have 0ohm between them. As far as I remember about anything in electronics, the positive and negative should never be a closed circuit..

Edit:
according to wiring diagram, this now makes sense. just wanted to clarify for future people who have issues.
Also the relay for the air pump is the ORANGE one.. some sources around say its the black one above the orange one. the relay is k6304a

[igeak691]

I think someone has messed with this before and swapped the relay wires around. Testing with my dad, the 50A fuse upstream of the relay is connected not to terminal 30 as it should but to 87. I want to see if this was tampered with as it doesn't make any sense why it would be swapped. Is there a way of removing the box that holds the relay and fuses?