Hi,

I read this in the September issue of Motor Age. You can find it on motorage.com -- look around for back issues of the magazine.

Anyway, it's a site for techs and shop owners. They have some interesting info and MotorAge magazine.

In the September issue, somebody wrote about a Mercedes with a bad A/C. It was not pretty.

The shop was probably reasonably competent, but probably had never dealt with M-B.

When they checked out the vehicle, they thought that the A/C clutch wasn't engaging. So, they applied 12v to the system -- no change. Ordered and installed a new compressor.

They jacked up the vehicle and then had to wait for parts. WHen reinstalled, same problem and more. Severe issues if they inserted the suspension compressor (self levelling system)fuse.

Brought in an outsider for help. He wasn't an expert, but he detemined the following.
- A/C doesn't have a clutch -- it's output is regulated by the computer. 12V apparently fried some things.
- Apparently the suspension tried to level while the vehicle was jacked up. Didn't matter that the key was removed. This cause d\some damage as parts were loose to allow installation of the new compressor and some other stuff.
- Outside tech found that the rear fuse block had been damaged -- but wait there's more ! Replacement requires reprogramming.

With the grace of God, and a good stout stick ( and some further help), the vehicle was finally repaired. Didn't mention who paid for what.

Tragic story of the state of repair these days. Probably a decent repair shop that got in over its head with the M-B system. Repair info is hard to come by and sometimes the design seems to be alittle odd.

For instance -- why does the auto suspension leveller work without they key -- also seems to have not activated right away.

And why should replacing a fuse block require reprogramming -- sheesh.

Not that the shop didn't stumble a bit (didn't notice that there was no A/C clutch), but it still shouldn't have been the catastrophe that it turned out to be.

M-B makes a lot of complex systems, but they're not the only ones.

hj

 

The question is, Is MB and it's rivals protecting their brand by making vehicles so complex that the dealer is the best option for service?

I say, yes.

 

I agree---it would seem Volvo is another of those guarding their cars from DIY repairs.

Not trying to be too paranoid but I'm sure at some point manufacturers questioned how to better direct or require their franchise owners to be the one and only service outlets. While the European car brands seem to practice this most frequently its a creeping situation, most likely coming to a brand near you any day now.

Along with the dwindling lot of interested and motivated service technicians making vehicles more self-diagnosing via computer control takes a bit of troubleshooting skills out of the repair equation or at least narrows down possible trouble points to a few components.

Then again this being America whenever someone throws up a roadblock and someone can figure a way to make money from creating work arounds we won't completely unable to DIY some of our own service work.

 

All of the European makes have made it very difficult for anyone other than their dealers to work on their cars. When I had an auto shop a few years ago I had to turn away some of the European cars. I had several very expensive scan tools, but I couldn't read their codes. I even had a Master Tech that was one of a handful in the US that had EVERY Master certification from ASE. He wouldn't touch these cars because he couldn't get enough info to be able to fix them.

 

Another great reason to drive

 

Fords can be just as bad. 2nd and 3rd gen Explorers will give false O2 sensor readings on a generic scan tool. Luckily my scanner has Ford capabilities, that one had me running in circles for a bit.
Mercedes are overly complicated POSs, I know I work on enough of them. My boss thinks ML320s and ML430s are made from solid gold and won't hear of it when I try to explain the reality of how it's not gold it's more like poo yellow. Everything is stupidly complex. Take for example the parking brake cable. Normal cars and trucks have an adjustment either in the drum, in a turnbuckle, or at the handle. Not Mercedes. They have this obnoxious cam system where the cables split that has an hour long adjustment procedure. I believe there's a saying about idiots making things more complex but it takes a genius to simplify- MB sure seems to have idiots.

 

I worked for Getrag for a couple years. That was (they sold out to GKN) a German manufacturing company. They made transmissions, axles, and all wheel drive systems.

They LOVED to make things complex. I think it is part of the German heritage. The more complex, the better.

 

The Germans did that with their Tiger tanks.

 

I doubt it. There's lots of independent shops that specialize in repairing Mercedes vehicles.

 

Absolutely. The Ag sector has been doing that for years. A JD dealership literally cannot repair an Agco or CIH tractor. They need the proper computer programs. Independent repair shops are relegated to older equipment, much of which is still operating because of its robustness and simplicity.

Everything built in the last 20 years has been engineered to fail.

 

as for fuses boxes.. Dodge trucks.. 04 to 07 has a smart fuse box .. with circuit board issues.. a replacement after the install the computer must be reprogrammed to accept a new fuse box... Dealer Only.

 

On the newer BMW's if you change the battery you have to tell the computer a new one was installed.

 

The Mercedes ML has a computer in the shifter. It is not waterproof. My boss has now found this out twice, apparently when you spill a Bubba Keg of water in it going down the freeway it immediately goes into limp mode aka first gear.