Hey folks,

First time owner, all of 3 days now, of this beautiful car (I'll post pictures soon). Bought it knowing the A/C was somewhat troublesome but I fell in love with the car. Previous owner was pained to sell after owning for almost 10 years but I assured him I would care for his beauty with the same love.

Most pertinent issue at hand is the A/C (Climate Control is what I'm being told is the proper term for Mercades owners?). I'll do my best to describe the issue and all info I've found by searching in hopes to narrow down possible scope of issues (and again I'll post pictures soon, just need to know what to post for help).

• Symptoms: Turn blower to full (top right button), set compressor to Top/Bottom (White arrows up and down, button to right of defrost), Temp wheel set to min (blue, white dot). Door side vents and defrost will blow cool air with slight to moderate force for 2-20 minutes (varies), center vents will not blow. Air is cool after a few moments (60F) then chilly (40-30ish F) and windshield fogs rapidly. Over time the air force dwindles to nothing, can still 'feel' and hear the blower or compressor running and putting hand to vents can feel coolness though no air force.
  
• Attempts at resolution: The CCU (123-830-12-85-M250 ) was replaced by previous owner as a hopeful fix for the problem, was a rebuilt bought from Pelican Parts, however issue was not resolved. Previous owner made no mention of any cleaning to the system.
  
• What I have found: I've read through the forums, performed some searching over the last 24-48 hours and have found some possible solutions.
  
  1. Fuses (#5 and #8) relate to the climate control system (?) need to be tested/replaced
  2. Vents are controlled by vacuum(?), need to pull dash to inspect vacuum system lines, check valve (123-800-00-78-M22) and possibly change-over valve (000-800-04-78-M22)
  3. Possible blower controller (Though wouldn't replacing CCU resolve this?)

All advice would be appreciated prior to my working on the vehicle!

So after some further inspection prior to removing the dash (and some help from a car loving friend of mine) we found that it is probably the blower motor.

While sitting in the car, he slammed his fist under the glove back (tech tap) and the blower began to push out cool air again.

Take off the cover under the dash on the passenger side- blower is behind it. Disconnect the wires, pull the blower and clean it. Lube with a few drops of ATF, clean the wiring connectors and the plug and put it back together. Should give years of further service.

If that is what is wrong with AC you are way ahead.

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95 E300D working out the kinks
77 300D, 227k, station car
83 300CD 370k, gone away
89 190E 2.6- 335k, no more
79 VW FI Bus- 145k miles, summer driver
59 VW Beetle ragtop- 175k miles
12 VW Jetta- 160k miles

1. Blower motor is your problem for working intermittantly. As my83300cd said on passenger side, remove cover looking up. Search w126 blower motor removal and I'm sure you will find some good info with probably pics how to do it.

2. Your center vents not blowing and cool air from defront is vacuum pod (element) behind center vents is the issue.
To change it, Remove glove box. look left hand side top inside and you will see one vacuum element. You need to change it with new one and your center vents should be working.

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1) '04 S500 Gold/Beige......120k Miles
2) '93 300E 2.8...Green/Tan MBTex..........202k Miles(and going)
3) '89 420SEL...Light Blue/gray Leather....155k Miles (Retired )