Air suspension drive box

Had a bit of a problem with my air suspension for a while, mainly because i`ve just been putting off doing it but i was told the problem i have could be the drive box, so my question is if i change my drive box for a new 1 will it need to go on diagnostic or will it work right away if it is actually the problem?
The reason i ask if it will work right away is i was told that it does not log a fault when its buggered it just doesnt work.

ANR3900,if my addled mind is still playing ball.Bolt on job,no need for Testbook.

hi m8,do you mean the valve block?,this is under the bonnet on the ns inner wing,the compressor is in there as well,if you change either of those components in shouldnt need to go on test book unless a fault is current and on your display.

An update on the problem; after replacing the drive box for a new 1 i still have the same problem; the pump wont come on unless the relay is taken out and i bridge it just to pump the car up to a descent height, it has no fault on the dash so I am clueless as what to do next.

Sounds like the thermal switch may have gone open circuit in the compressor.Try disconnecting it then with multimeter on a resistance scale check between the orange and black wires - it should be zero resistance.If its open line then the switch has failed,making the ECU think the comp has overheated,so it wont run it.

eightinavee said:

Sounds like the thermal switch may have gone open circuit in the compressor.Try disconnecting it then with multimeter on a resistance scale check between the orange and black wires - it should be zero resistance.If its open line then the switch has failed,making the ECU think the comp has overheated,so it wont run it.

Click to expand...

Is the thermal switch actually inside the compressor?

Yes its inside the end cap of the motor next the brushes.

Thanks Jon I will get to it when the misses isnt using it and its not dark and various other excuses

eightinavee said:

Yes its inside the end cap of the motor next the brushes.

Click to expand...

But he says he can jump out the relay to get it to pump. The thermal cutout must be ok. There would be no way to bypass the cutout without jumping it locally on the compressor. Even with the relay jumped out it would still need to pass through the cutout. Unless the cutout just signals the ECU.

Mud Flap said:

But he says he can jump out the relay to get it to pump. The thermal cutout must be ok. There would be no way to bypass the cutout without jumping it locally on the compressor. Even with the relay jumped out it would still need to pass through the cutout. Unless the cutout just signals the ECU.

Click to expand...

You answered your own statment,the thermal switch only provides an earth path to the ecu for signal purposes,when it goes open circuit the ecu will not switch on the comp.

Anyway thanks for the advise I will have a look at it next weekend and if i get stuck, let me rephrase that, when I get stuck I will be back on here.

Finally sorted, it was the thermal cut out.
I put a new pump in and and its minted.