Hallo,
I need soem help to fix my A/C in my w 124 300 D Turbo 1992
- i have cold air if i put on roller in BLUE compressor run OK.
- I have hot air if i put on roller in RED .
but in between temperture seems go up and down .¨
If i disconnect DUO valves i have hot water.
I checked with multimeter and OHM change when i move the roller on A/C control.
It can be some evaporator senders or Inside cabin sender?
It is hard to remove them?
Thanks a lot
Alberto

In the front of the roof, the assembly that has the sunroof control and the map and cabin light, there is a little grid which is the cabin air intake to draw air past a sensor. Cut a little square of paper to fit over this grid, and see if that will be held in place by suction when the HVAC is running. If no suction, then no air flow over the sensor, and erratic temperature control could result.

This is just one of about twenty tests in the HVAC manual.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

In case that was a question, the duo valves are supposed to go wide open with no electrical signal.

Sixto
83 300SD
98 E320 wagon

Cracked solder connections in the pushbutton unit are common especially around the pushbutton switches and the temperature adjust potentiometer.

thanks i will check

Hey Alberto,

Check out the link below to address your A/C issue. If you have anymore questions, feel free to post a Comment just below the article and we'll do our best to give you more details. Best of luck!

Mercedes-Benz W124 Blower Motor Replacement | 1986-1995 E-Class | Pelican Parts DIY Maintenance Article


-Dmitry