The Airconditioner was set at 74 F (ambient 87). It spontaneouly went from cooling to max. heating. The center went shut down, blower went to high and air started coming out of side, lower and defrost vents.

I moved the temp adjustment dial to max. cooling and it went into cooling mode again.

Since then, I have moved the temp selector wheel to 74 and it has been working properly.

The car has a new aspirator blower and interior temp sensor and the system has been working without any problems except for a slight bias towards cooling the car more than the temp indicated on the adjustment wheel.

In the mornings (56 F), if I select the "compressor on" mode, I have to adjust the wheel to about 77, otherwise it makes the car too cool.

In the afternoon (85), I have to adjust the wheel again, but everything else works like it should, after some time the blower slows down and the temp is maintained.

__________________
Zafar
94 E320 58000 Miles

The problem is probably in the wheel control that adjusts the temerature. I was able to fix mine.

__________________
Earl



1993 190E 2.3
2000 Toyota 4x4 Tundra

"The temperature control wheel is attached to a rheostat that controls the temperature settings. The pins from the rheostats (twins sitting side by side... one hot the other cold) can crack at the solder points and become disconnected from the circuit board. If this is the case you will see the crack around the pin where it is soldered to the circuit on the board.

Either resolder the crack or solder a thin wire from the cracked pin to another pin on the same CIRCUIT of the board.

If you are able to do this repair I will tell you how to take the control module out and then disassemble it."


Earl,
How did you take the control module out?

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Zafar
94 E320 58000 Miles

We have different cars. On mine you begin by taking out the screw behind ash tray... and as things come off more screws will be revealed.

Maybe someone with your model can tell you more precisely.

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Earl



1993 190E 2.3
2000 Toyota 4x4 Tundra

Time has finally come to fix the bad connection. If someone has taken the control module out, what is the correct procedure and how long does it take?

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Zafar
94 E320 58000 Miles

If you are familiar with the procedure you can have it out in about 15 minutes but it may take you a half hour or so when doing it for the first time.

Do a search on my posts. I have outlined how to make the repair in detail a couple of years ago.

__________________
Earl



1993 190E 2.3
2000 Toyota 4x4 Tundra

I ended up replacing the whole climate control unit. Temperature is being maintained properly now.

__________________
Zafar
94 E320 58000 Miles