After trying a used Climate Control Unit, new fan resistor etc, I finally bit the bullet and bought a rebuilt climate control unit.   This solved the problem.   In retrospect I probably didn’t need to buy the resistor and I certainly didn’t need the used CCU.     It also pays to shop around as a rebuilt CCU was much cheaper directly from the source than the usual online parts vendors.   I got my from ProgRama Inc.

This job should have been simple.     As I discovered earlier, the blower fans are different LHD to RHD.   This meant I re-used the housing from my old one.   What I didn’t realize until I had it all fitted was that the fan direction is obviously different too.   My new blower was blowing, but no air was coming out.    In the end I had to reverse the terminals of the controller to get air flow through the vents.

The aftermarket controller was slightly different at the back as well, so I had to file down part of my housing to make it fit.

The next steps will be to have the new A/C compressor I have purchased fitted.   This is not something I am equipped to do myself.   In any case, you need a licence to handle refrigerant in Australia.

Overall I like the W126 climate control system when it works.   However, I would have preferred a system with manual climate control.   Mercedes-Benz Australia to my knowledge ordered all the 2nd generation models with Automatic Climate control.   This would mean finding a private import with a manual set up.   A rather difficult task.

The post Finally, a working blower motor appeared first on .

I was able to check this by bypassing the Klima relay, and the compressor popped the fuse even when the engine was not running.   This did not happen when the compressor was disconnected.

I have since sourced a new compressor which will go on in November when the car goes for its rego.

The blower motor was also very noisy and would turn on and off on its own.   I first thought the issue was with the aspirator fan, which is a small fan to blow air over the temperature sensor.   These are known to get very noisy with age.   Only problem was somebody had completely removed this fan from my car.      Next, I was able to determine that the main blower fan was the problem.     These are still available for a reasonable price, unlike the 107 fan that took me years to find one that was not seriously overpriced.    The one I got was for a left hand drive car (they are different in the 126), but this is not a problem as the plastic housing can be re-used and the actual fan that wears out is the same.

The blower was refitted and didn’t work.   Next step was to test both motors on a spare battery.   When connected up to 12 volts both motors worked well, although the old was was noisy as expected.    Next step was to check if the motor was getting voltage, and it was. 

This meant that either the resistor that controls the blower speed, or the climate control unit itself were not working.   The resistor can be seen in the photo above and is known as the porcupine.   The blower is fed 12v through a dedicated, high amperage fuse.   The CCU supplies a current to tell the porcupine how fast to run the blower.   I wasn’t able to detect that control voltage from either of the two CCUs I have.  This may have led to trying another CCU, but I decided to change the porcupine first.  They are much cheaper than CCUs and known to fail.     Now I have two porcupines, two CCUs and still not even a working blower motor, let alone working climate control.

I did manage to find a company that offers rebuilt CCUs at a much more reasonable price than the main parts supplier (and looking at the pictures, seems to be the source of their inventory).   I have ordered one of those, and hopefully it will at least get the system and working, ready for the new compressor.  They suggest some checks on the resistance values from the monovalve and Aux water pump. Finally some good news, they are working as expected.

(Update: October 27, 2017 – The blower motor issues were fixed with an updated CCU/Porcupine)

The post W126 Climate control woes appeared first on .

A couple of years ago, I purchased a new motor assembly and fitted it to my existing blower housing, fan cages, capacitor block etc.   This got rid of the irregular operation, but not the noise as periodically I would need to remove the blower and adjust the fit of the motor inside the housing – the housing was cracked and the motor just didn’t sit right.

A couple of weeks ago I spotted a brand new OE W107 blower for sale on US ebay for $200 and pounced on it.   At the same time I also got a new gasket and blower cover as my cover was cracked too.

I fitted the new blower today and so far so good – I am missing one screw for the cover so I’ll need to follow up with that later.   All I had to re-use was the old capacitor block and power cable.

To change the blower, the cover just comes off with phillips head screws, the capacitor block comes off with another two phillips head screws and the blower is held down with 11mm nuts.

The W107 blower motor cover has a plastic piece to protect the capacitor block.   It is broken off on most cars.

The post 450SLC gets a new blower appeared first on .

About two years ago I ‘rebuilt’ the blower with a new motor, but with my existing case and fan cages.   A new W107 blower motor from Mercedes is prohibitively expensive, but you can get the internal motor on ebay.

The problem with this, is that the fan cages are friction fit on the blower motor shafts so once you have removed them and put them on the new blower motor, they are never as tight as original.

In addition, when I replaced the motor last time, I noticed the gasket was perished, so I purchased a new one for the job:

SLC blower gasket

Removal and replacement of the blower motor is fairly straightforward.   You need a short handled Phillips head screwdriver and a 10mm socket and extension.

The motor case is held together with clips that can be removed and replaced by hand, although care is needed with 30+ year old plastic.

Blower Installed

The gasket is important so water does not get into the blower compartment.

I had to use a screwdriver to carefully re-align the fan cages on the shafts and in the housing.   The blower is working well again, it remains to be seen how long that lasts.

All Finished

Update: 10/2013.   I found a New Old Stock W107 blower motor for USD$200 and installed that instead.   Much better.

The post The SLC blows again! appeared first on .