BrakeFade

If anyone has a schematic for the Airmatic control, I would really appreciate a copy. I keep blowing fuse 37 (15a) in the driver side dash. I get the display malfunction error and both airmatic control buttons at the shifter base lose power. Once I replace the fuse everything works fine. But it eventually blows again. Where is the airmatic control unit located? Also, I replaced the pump 3 months ago.

I'd like to trace out this little gremlin...

Any help is appreciated.

2004 e55

Plutoe

To be correct you really need to post you VIN----all else is speculation!

BrakeFade

WDBUF76JX4A544366

Plutoe

Fuse 37 protects the Airmatic control module N51,therefore you have a bad module. Replace the module and enjoy the ride or live with it!

BrakeFade

I was thinking a bad module as well. Do you know if I have to have the module calibrated or setup by the dealer? Or is it just plug & play?

bbirdwell

Under the passenger side floorboard.

BrakeFade

So I pull the carpet back on the passenger side and I'll see it staring at me?

Thanks to to everyone for the help!

bbirdwell

here...

BrakeFade

Thanks!!!

Will I need to have the module programmed or setup by the dealer? Can I just purchase a used working module, replace it and go about my merry way?

bbirdwell

It should be plug and play but...(you knew that was coming, right?) you should have the suspension calibrated and the values programmed into the module.

Basically, you use the diagnostic system to add/subtract air into the air springs until you meet the following conditions:
-Front control arms within the angular range of 2.8 to 3.4 degrees (inboard end of control arm higher than the outer end).
-Rear axles (the stub shafts) within the angular range of -0.9 to -1.5 degrees (inboard end lower than the outer end).
-sensor voltages within (IIRC) 2.2 to 3.0 volts.
-Enter angles into the diagnostic system and press "enter".
-If within factory parameters, the control module writes the new values into memory and can now properly control your entire suspension. It does an awful lot of calculations in that little box.

A Romess is the approved and expensive way to calibrate; you can do so with a free inclinometer app on your cell phone. You do need access to Star.

If you can't do it, the dealer can do it or should be able to do it.

BrakeFade

Thank you bbirdwell.

I've been seriously considering coilovers and now it seems I'm going to drop a couple hundred bucks on a dealer visit to calibrate the Airmatic controller after replacing it. Good news is I can pick up a used airmatic controller for about $60 off eBay. Hmmm, decisions decisions....

bbirdwell

If the dealer won't or can't do it, use the forum to find a member up in DFW with a Star system (there are several members up there) and I'll send you instructions on how to calibrate. It's not difficult at all and an inclinometer app does the trick. Donate a six-pack of beer and a pizza. Search on W211 suspension calibration bbirdwell and you'll find a few notes. If you want more, PM me and I'll send you some more info.

Coilovers are cool and what not but I regard them as a one-trick pony; I actually like my air springs as they allow me to select the ride quality I desire at the moment.

BrakeFade

I will do that.
Next thing for me to do is pull out the controller when I get home and get a part number. Unless, you happen to know it right off the bat.
Thanks!

seanol

I'm in Garland with Star if you want to get it done.

Sean

BrakeFade

Thank you, Sean!
I will contact you when I get it swapped out. I'm in Florida this week and plan to replace it when I get back in. I just ordered the unit today, so I'm hoping it arrives before I get back in town. It would be nice to meet another local mbworld member. I'm in Denton.

BrakeFade

Updating everyone on this....


I get home yesterday and replace the Airmatic Controller with a known good unit. Drove it around town for about 30 minutes, make a hard turn into a parking lot and F37 blows. Stop & replace the fuse, do some hard cornering in an empty parking lot and F37 blows again. Replace the fuse and while idling, cycle through raise, dc1, & dc2. I immediately notice the pump is not always coming on. When it does come on, the car doesn't raise as high as it did when I first replaced the pump. Drove it around with some hard cornering thrown in and it hasn't blown a fuse since. The pump still only comes on intermittently when manually controlled.

My my first guess is the pump has been the culprit. Coming on during driving and blowing the fuse (probably overuse from leaky suspension). Now that it's failing to come on sometimes, the fuse doesn't blow. But why F37?

I replaced the pump 3 months ago because it just flat out wouldn't cycle on anymore.

Im going to swap out the Airmatic controller back to the original unit tomorrow and see what happens....

bbirdwell

If you can PM me your VIN I can take a look at the schematics for your build and let you know what else, if anything, ties into fuse 37. May take me a day or two between work and what not.

This is where it would be really nice to throw it on the diagnostic system and see which part of the airmatic system shows the Failure code...now is the time to check the wire harnesses to the sensors and compressor; in the past I have found one sensor harness dangling abrading against a piece of the suspension. When the flexible service system says, "Inspect", I literally lift the car, pull the wheels, and crawl all over/under that car with a flashlight inspecting everything that looks like an electrical harness.

BrakeFade

Sensor would make a lot of sense since I'm certain it feedbacks directly to the controller. That's why I was scratching my head about the pump thing. The hard cornering blowing a fuse would be a good indicator as well. I'll pm you shortly. Thanks!