QuestionHi,I have a problem with air con on this car I just purchased.Could not fill with gas,I changed equaliser valve.Then filled with gas,pump working fine,clicking in and out,pipes on compressor ice cold but only warm air blowing into cabin?I was wondering if somebody could help.Thanks
AnswerYour system could have several issues or just one. The ACC version II has the dreaded servo -(Delco #15-5306 (Mercedes #000-830-03-84) Air Conditioning Climate Control Servo) and that could be the culprit, it could also simply be a vacuum leak to your valves that control the AC flaps, or the temp control wheel
You have to rule out each as you go, this is not an easy task .
Do you get heat? Does the temp wheel change the temp at all?
Can you hear flaps opening and closing?
Here is the way to test a few components ( copied from another post)
To check out the resister chain,
1. Remove the ACC amplifier (located to the right of the glove box)
and connect a ground to pin 3 of the connector plug.
2. At the servo electrical connector, connect an OHM meter between
pins 1 and pin 2 on the left of the connector.
3. Place the temperature wheel at max (85 degrees) and the resistance
should be between 2.2K ohms, and 4.7K ohms.
4. Place the temperature wheel at 65 degrees, and the resistance
should be between 1K ohm and 3.5 K ohms.
When you finish, re-install the amplifier.
If the circuit is open at any place in the resistor chain, the result
is heat. If the chain is OK, then the problem might be the amp.
To check the amplifier, connect a voltmeter between pins 1 and 7. With
the ignition switch in the on position, the voltage should be about a
volt. Move the temperature wheel from cold to hot. The voltage should
increase to about 5 volts, and when the servo finds it home, the
voltage will drop back to about a volt. If it does not vary, then the
amp is bad.
The servo (usually big black contraption under the hood) responds to
the temperature control resister chain. It has a small electric motor
that routes vacuum to control flaps, moves variable resister to send a
signal to the amplifier, and opens and closes the hot water valve.
The motor in the servo receives a voltage signal from the amplifier
that is located behind the glove box. If you want to test the servo
motor, remove the vacuum lines and the 10 pin electrical connector.
Pin one is on the right of the connector looking at the servo.
Connect a ground to pin 1 and +12 volts to pin 5. The motor should
run.
Reverse the wire and the motor runs in the other direction.
If the motor does not run (you can hear it), the servo is bad.
You might also have a shorted aux water pump. This electric pump is
located just in front of the servo. Disconnect the pump and connect it
Hope this helps
Ron
