Just in time

I have a 2007 gl450 that the front suspension works fine but the rear won't raise. Had the pass side rear airbag blow, changed it but rear still won't raise.

Could this have anything to do with the rear lifgate sensors?

I was reading something about another pump under the rear seat could this have anything to do with it?

Fourdiesel

Have you 'reset' the system? Some air suspension fixes/replacements require a reset.

alx

Correct. Airmatic needs to be reset via das when pressure has been leaking for a long period of time and the system has disabled the offending circuit. Replacing the faulty component is not sufficient in this case as you need to "tell" the system that it can pressurize that circuit again.

Just in time

I have had the truck at 2 diff shops and one says pressure relief valve in the compressor??? but why would the front work and not the rear? another says height adjustment sensor, but why would BOTH rears not do anything?? I'm really at my last nerve with this truck!! what kind of regular rear suspension can i put in this truck?

Just in time

could this have anything to do with the rear liftgate?

alx

no

Just in time

Could it have to do with the valve block?

alx

absolutely.

assuming airmatic reset has been performed and the problem is still present- the valve block is suspect stuck closed.

Just in time

I would assume the reset has been done it has been to 2 shops both with the star system. So besides the valve block could there be anything else that would give these symptoms? Thank you for your help!

alx

if the compressor is operational and can maintain pressure in the reservoir - the valve block warrants closer look.

there are star actuations for airmatic that will help troubleshooting the valve block.

Just in time

What parts are there? I Beleive it's pressure from the compressor to the valve block then to the individual corners? If not please inform me of the components I'm trying to research online but have no luck

Just in time

The resovoir has pressure the pump is working. So most likely the valve block?

alx

correct. the valve block/manifold is what is between the reservoir and the shock. if the shock is not inflating the valve block is either stuck or has no power.

as i said- there are manual activations in das that can be used to determine if valve block is good.

Just in time

Yes thank you! I just don't feel like getting screwed out of another $200 so I'm trying to figure it out on my own. If the front suspension is working I would ASSUME (I know, I know) that the block is getting power, so it would have to be a stuck valve. Or am I way off still?

alx

you really need das to confirm or reject any airmatic fault theory.

Just in time

How much does a Mercedes dealer charge for diagnostics?

alx

Whatever the hourly rate is. $140-150 / hour

Just in time

ALX I was wondering if I could disconnect the valve block, and switch the front and rear sides of it to see if it is indeed the valve block?

alx

Buy a Chinese das/ star. It will run you about $350 and will pay off he first time you use it.

Just in time

I understand that, but money is really tight right now and don't know if I'm going to be keeping the truck.

Can I do what I asked?

alx

Got it.

Never tried what you suggest, but I see no reason why this should not work.

Just in time

Cool, thanks for your help. Ill let you know.

Just in time

Switched the block around now rear rises and front wont. Should I now assume it is the valve block?

alx

This is not a conclusive test as it does not identify if the problem is mechanical (stuck valve) or electrical (bad wiring so the valve is not activated)...

shenminda

I have the same problem, How to reset the airmatic system?