CONVERTING A/C BACK TO R12 FROM 134A
Problem - I have converted my airconditioning system back to R12 from the 134A. All has been done correctly with replacing the receiver dryer, flushing and on checking, no bubbles in the system. It is cooling nicely and works better than before except the compressor cycles on and off even before the car gets cold inside.
Possibility 1 - There are 4 sensors
1) outlet a/c air at the top of evaporator
2) evaporator sensor - at the bottom of the evaporator ( opposite side to outlet sensor above, should be at the right bottom of evaporator for LHD )
3) cabin sensor ( at the passenger dash)
4) external sensor ( this is for cold weather ie snow to measure external temp) .
I suspect it could be the cabin sensor or the evaporator sensor , for cabin sensor it sends a signal to ECU as well so if u can turn ON heater and see if it functions as heater , if this works then your cabin sensor should be ok .
As for the evaporator sensor you can remove and test the resistance value . The moment you remove the sensor you will be able to tell if the sensor is the problem by roughly take note of the room temp and check the resistance value. it should be around the value show on table ( as below) . Or you can use hairdryer to warm it up and you can see the resistance value will move accordingly Temp vs Resistance value .
Problem - I have converted my airconditioning system back to R12 from the 134A. All has been done correctly with replacing the receiver dryer, flushing and on checking, no bubbles in the system. It is cooling nicely and works better than before except the compressor cycles on and off even before the car gets cold inside.
Possibility 1 - There are 4 sensors
1) outlet a/c air at the top of evaporator
2) evaporator sensor - at the bottom of the evaporator ( opposite side to outlet sensor above, should be at the right bottom of evaporator for LHD )
3) cabin sensor ( at the passenger dash)
4) external sensor ( this is for cold weather ie snow to measure external temp) .
I suspect it could be the cabin sensor or the evaporator sensor , for cabin sensor it sends a signal to ECU as well so if u can turn ON heater and see if it functions as heater , if this works then your cabin sensor should be ok .
As for the evaporator sensor you can remove and test the resistance value . The moment you remove the sensor you will be able to tell if the sensor is the problem by roughly take note of the room temp and check the resistance value. it should be around the value show on table ( as below) . Or you can use hairdryer to warm it up and you can see the resistance value will move accordingly Temp vs Resistance value .
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