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Question on A/C

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Almost 3000 hrs on my '99

Excessive Blowby/crankcase Pressure

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Something weird happened today. The wife was driving her truck and decided to turn on her Air Conditioner. Unfortunately, it turned the vent on... but never engaged the Air Conditioner clutch.



Does anybody have any ideas as to if this is an easy fix or do I need to take the truck to the local Stealer??



Also, as she got home and pulled in the driveway her dashboard started dinging at her and the air bag light came on. Could this be linked to the Clock spring??? Even though it has already been replaced?



Thanks



Kev
 
It could be low on the 134. If there isn't enough in the system, it won't run. Might do a quick check of the wiring connections.

Michael
 
I checked the wiring and it looks fine. The horn works. Also, I had the wife start the truck, then turn on the A/C. I sat their and watched it... the clutch would engage for about 2 seconds, then disengage. Engage, Disengage. . over and over again.



This doesn't sound good... .





Kev
 
This sounds like the compressor is locking up or the only other thing I can think of is it may be low on 134. I can't remember now if our dryers have a sight glass or not. If it does, look for bubbles in the glass window. a compressor can lock up from excessive head pressure caused by the condenser getting full of bugs and the system overheats, causeing the headpressure. Have you got an air hose? Could try blowing air from the back of the radiator to see if anything comes out. Do not use water, makes it worse.

Michael
 
my ac guy says that there is an a/c cycle switch that he has had to change on dodges before. I thought i saw a tsb on somthing like that. ill look into it further. . RRR
 
Thanks guys... we have decided to take the truck to the local stealer. I checked everything out and it looks fine... it just don't work.



I don't understand why all the sudden though... now that the AC has stopped working what is the deal with the Air Bags??? The truck keeps dinging at us telling us there is an issue, the airbag light lights up, then goes out. Any ideas? Can these 2 problems be related to one another??



Thanks



Kev
 
The A/C problem is almost certainly low refrigerant (R134a). There is a low pressure cutout switch on the system which will shut the compressor off if the pressure on the suction side of the compressor gets too low. So, with low refrigerant, the static pressure might be fine, but when the compressor starts, it pumps R134a causing the pressure to go too lowr on the intake side, and the cutout switch stops the compressor. That's why it runs for a couple of seconds and then stops. As soon as the pressure comes back up (from the R134a flowing around the system), it kicks in until the pressure drops too much.



The reason for the switch is to prevent the compressor from running when there's too little refrigerant. If it can't pump refrigerant around, it can't move the oil around, and the compressor will seize.



The reason it happened suddenly is that you finally had enough leak out that the low pressure switch started turning the compressor off.



As for the airbag stuff, I have no idea, but I doubt it's related.



-cj
 
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