3 Level pressure switch
08-22-2005, 05:48 AM
#1
Racer
Thread Starter
3 Level pressure switch
As far as I understand it, the 3 level pressure switch of the a/c system does various functions.
- There is the “high/low pressure”, which closes contact between 2.5 and 27 bar to ensure the system does not work without gas or with too much pressure.
- The other side, “mean effective pressure”, close it contact at 17.5 bar. FIRST QUESTION: Is this only to turn on the high speed of the condenser fan?
Now, since I retrofitted a system and was not sure about this I did the following wiring:
A switch gives signal to a relay if a freezer switch is not activated and if the “high/low pressure” side of the 3 Level pressure switch is closed. This relay outputs a earth signal to:
- Pin number 8 on connector T34 to turn on the high speed velocity of the condenser blower.
- Pin number 8 on the T5 connector to signal the ECU.
- Pin number 13 on the T5 connector to further signal the ECU and to signal an additional relay on the engine compartment that turns on the actual compressor.
It is clear that I should engage slow speed and use the “mean effective pressure” side of the 3 Level pressure switch to turn on the high speed, but: SECOND QUESTION: Do I need to remove the signal from the low speed of the condenser blower before I give a signal to the high speed?
- There is the “high/low pressure”, which closes contact between 2.5 and 27 bar to ensure the system does not work without gas or with too much pressure.
- The other side, “mean effective pressure”, close it contact at 17.5 bar. FIRST QUESTION: Is this only to turn on the high speed of the condenser fan?
Now, since I retrofitted a system and was not sure about this I did the following wiring:
A switch gives signal to a relay if a freezer switch is not activated and if the “high/low pressure” side of the 3 Level pressure switch is closed. This relay outputs a earth signal to:
- Pin number 8 on connector T34 to turn on the high speed velocity of the condenser blower.
- Pin number 8 on the T5 connector to signal the ECU.
- Pin number 13 on the T5 connector to further signal the ECU and to signal an additional relay on the engine compartment that turns on the actual compressor.
It is clear that I should engage slow speed and use the “mean effective pressure” side of the 3 Level pressure switch to turn on the high speed, but: SECOND QUESTION: Do I need to remove the signal from the low speed of the condenser blower before I give a signal to the high speed?
