Airmatic Relay Issue
Fault was the green Tyco relay in the engine compartment relay box. (Box is on the front passenger side, relay is 3rd from left)
Replaced the relay with an updated Hella unit from the dealer, ($40
) and problem solved. Hope this helps others.FYI in checking around, seems like the factory Tyco relays are "not as strong" as the Hella units, so would advise replacing before you have an issue.
Switch the Tyco relay ASAP for the Hella unit.
The relay price will pale in comparison to the Airmatic Pump price. These pumps can run from $380-550 for just parts depending on where you find it.
Be proactive on this one!!
It is a green relay 3rd from the left in the front engine compartment fuse box. Make sure the replacement is a Hella unit. The ones at parts stores may not be correct as this relay is what I call a double throw, single pull. This one looks like it sends current to BOTH 87a and 87 pins, not one or the other.
Hope this helps.
Last edited by dgiturbo; Apr 10, 2012 at 07:46 PM.
I have just had this exact same problem. The compressor wouldnt stop working even after the car was off, locked etc. After some helpful advice from MBWorld i took the 40A fuse out to save a full meltdown of the pump and a dead battery in the morning..
The missus used the car during the next day with the fuse out, the only effect being that the front of the car sank down a bit on the air springs. Anyway, i popped into the stealership and bought replacement relays, apparently the Hella ones are now standard replacement parts (complete with MB logo on) so i got two as there are two of the nasty green tyco relays in the fuse box.
I replaced the relays and all is ok now. Im just recovering from an air spring replacement and couldnt handle another repair.. just thinking about the bill from that brings me out in a cold sweat.
Anyway, i posted a few pics as a guide to anyone with a W164 having a similar prob or simply wanting to replace the nasty green tyco relays. Hope it helps.

PS Part nos. as follows:
Old Part - Tyco 002 542 2319
New Part - Hella 002 542 7619
I have a Tycos in the 1st relay spot and a Hella relay in the 3rd spot. Can they be swaped in positions for each other?
I moved the Tycos relay to the 3rd spot where the Hella relay was and moved the Tycos to the 3rd spot to see if anything changed. But still nothing, my compressor cannot be heard with the car running. The relays look like the same type of relays. What are the chances that both Relays are bad at the same time?
I have just had this exact same problem. The compressor wouldnt stop working even after the car was off, locked etc. After some helpful advice from MBWorld i took the 40A fuse out to save a full meltdown of the pump and a dead battery in the morning..
The missus used the car during the next day with the fuse out, the only effect being that the front of the car sank down a bit on the air springs. Anyway, i popped into the stealership and bought replacement relays, apparently the Hella ones are now standard replacement parts (complete with MB logo on) so i got two as there are two of the nasty green tyco relays in the fuse box.
I replaced the relays and all is ok now. Im just recovering from an air spring replacement and couldnt handle another repair.. just thinking about the bill from that brings me out in a cold sweat.
Anyway, i posted a few pics as a guide to anyone with a W164 having a similar prob or simply wanting to replace the nasty green tyco relays. Hope it helps.

PS Part nos. as follows:
Old Part - Tyco 002 542 2319
New Part - Hella 002 542 7619
Peace and love.
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le_barn, Thank you so much for this post from 2013!!!! I have a 2012 GL450. I already paid to have the rear air struts swapped out along with the compressor. 3 years later I had the front air struts swapped out and the distributor and all seemed well until.... the compressor was running constantly then all of a sudden it wouldn't even kick in anymore and the front just stayed down. In my great frustration I was getting ready to throw even more money at it. But this first picture in your post with someone swapping out that big 40amp fuse made me realise that the compressor has a relay and (to my own amazment) a FUSE. I tried and sure as heaven the compressor lifted the care right back up. You saved me A LOT of money as I was just gonna go to the dealership an ask them to put in all brand new parts. Thanks again!!!
Thanks
Lanny
I have just had this exact same problem. The compressor wouldnt stop working even after the car was off, locked etc. After some helpful advice from MBWorld i took the 40A fuse out to save a full meltdown of the pump and a dead battery in the morning..
The missus used the car during the next day with the fuse out, the only effect being that the front of the car sank down a bit on the air springs. Anyway, i popped into the stealership and bought replacement relays, apparently the Hella ones are now standard replacement parts (complete with MB logo on) so i got two as there are two of the nasty green tyco relays in the fuse box.
I replaced the relays and all is ok now. Im just recovering from an air spring replacement and couldnt handle another repair.. just thinking about the bill from that brings me out in a cold sweat.
Anyway, i posted a few pics as a guide to anyone with a W164 having a similar prob or simply wanting to replace the nasty green tyco relays. Hope it helps.

PS Part nos. as follows:
Old Part - Tyco 002 542 2319
New Part - Hella 002 542 7619
Fault was the green Tyco relay in the engine compartment relay box. (Box is on the front passenger side, relay is 3rd from left)
Replaced the relay with an updated Hella unit from the dealer, ($40
) and problem solved. Hope this helps others.FYI in checking around, seems like the factory Tyco relays are "not as strong" as the Hella units, so would advise replacing before you have an issue.
https://www.mbdirectparts.com/search...str=0025427619







