Ecin

Is there a way to test the airmatic pump outside the vehicle? w211 2003 E320

kered

How many wires goes into the pump?? A quick look at a schematic and it seems to show four wires going into the pump. Two are for the pressure release valve and two will power the pump. You should have a red/white wire and a brown wire going into the pump for power and ground. The wires should be of thicker gauge then the other two wires. If you apply 12v to the red and white terminal and ground to the brown terminal the pump should run. Only do this for a short period of time though.

ponski

hello, i just took out my pump tonight and did the test described in this post, the pump didnt run, bad pump i guess. BUT i also put a voltage meter on the thicker gauge wires that i unplugged from pump underneath the car. I cant read any voltage while the car engine is running or key in ON position. I DO get 9volts on the smaller gauge wires. So i checked fuses 9, 32 (40Amps) and 46, and they are all good. i also got 80ohms on the relay (label O) between 2 of the 4 pins. Before I took out the pump, I removed the host going to the pump filter and i dont feel any air and I didnt feel that the pump was running as well. my question is, is there suppose to be voltage coming from the thicker gauge wires when its not connected to the pump?

Thanks for any feedback
ponski
2002 S430 W220

sthoms

What came of your testing?

Can you check for 12v at the wiring harness?

My pump will not run when 12v is applied to the pump directly. (+12v to Red/White, Ground to Brown) Should it?