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Discussion Starter · #1 ·
I just converted my Diablo a/c back to R12 from 134A to hopefully cool better in these hot Louisiana summers. I have a stock of R12 I purchased years ago. Replaced the drier and flushed the lines out. Pressures are right and no bubbles in the sight glass. It works better but still the compressor cycles on and off before the car really gets cool inside, even on LO. I have read there are two sensors, one for the interior temperature and another for the evaporator temperature. I hate to just throw expensive parts at it. Has anyone else had this issue before and what did you do or replace?

Thanks...
 

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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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Discussion Starter · #8 ·
I'm telling you, I don't know about these so called high end shops that work on these cars. After pulling the evaporator sensor out (it took some pulling), I looked at the parts diagram and it shows a rubber bushing that it is supposed to fit into. Well.... some shop must have replaced it during the prior owners time with the car and instead of purchasing the bushing, they just filled the hole up with putty. I got the most of it out... I mean dang, your getting paid $150-200 per hour, do a respectable job! Probably the same shop that would not stand behind the transmission leak that they supposedly fixed before I purchased the car. Hand Finger Gesture Thumb Nail
 

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I have decided, looking forward, that when I have to kick some business or person out of my life for shady dealings, I will seek out two superior examples to replace them. Otherwise, the world keeps shrinking, and options are reduced.
 

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Discussion Starter · #11 ·
One more A/C question. My center vent does not work when pushing the center button to actuate it. It blow thru the center two vents all the time. The electro-valve that controls it, is the one towards the front of the car. I can take a test light and touch one of the terminals on the electro-valve and it will then actuate the door for the center vents, with a dim test light. The other terminal does not actuate the door but the test light is much brighter. Can anyone tell me how these work and if the electro-valve is actually bad? And do you have to take the dash out to access or change one out? I don't think I could change one from under the dash.
 
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