AC on the fritz

[tobaccogrower]

my ac on my 1993 started acting up yesterday. the compressor just stopped pumping. a few starts later the ac started working. i couldnt find a fuse for the compressor, just the heat/ac and it was a 30 amp fuse and in good order. are there more fuses somwhere besides under the column? anything else i should check?

 

[cerberusiam]

Check pressure in the system. Its probably low.

 

[HHhuntitall]

... . and maybe wire connections on firewall above passenger fender and at the compressor.

 

[DVolk]

should also be a relay , could be a bad wire as well

 

[Bob Beauchaine]

How well does your A/C work when it is working? Does it cool the interior or does it cycle on and off? There are three relays on the drivers side inner fender - one of these controls your A/C. The part number for all of these is the same so you can swap them to see if that helps. You can also check the A/C sight glass on the passanger side inner fender - if you are still running R12 you should see clear R12 flow in that sight glass - lots of bubbles indicate that the system is low and it should be recharged. When I replaced my charge air cooler (intercooler) I had a good A/C shop service it and they did a vacuum check and checked the systems high pressure portion with nitrogen. Since then the system works very well and that was about 7 to 8 years ago. Last but not least is there any blockage in front or in between the the A/c condenser, intercooler or radiator.



Bob

 

[mweiman]

There is also a fusible link on the driver side fender that could be getting a bad connection, I think it is an orange wire. Mine had a bad connection there and I also had to replace the relay after running it a few times. I just got mine working again after several years. I can get you a better description of the fusible link if you suspect it. I think the relay that runs the compressor has 3 blue wires and a brown wire, check for power there or jump around it to see if the compressor runs.

Matt

 

[tobaccogrower]

its still r12. system works awsome when working! i'm a farmer and have been irrigating lately and spend alot of the day in the truck checking the guns. alot of starting and stopping the truck. somtimes i'll start it and wont have ac. 10 minutes later when i start it it will work. also, yesterday it was working then just stopped with truck running. i'll check the sight glass, link and relays. i'll aslo clean the connection to the compressor. my megacab ac is also dying, but thats another thread. thanks for the help guys.

 

[DVolk]

have you checked the switches on the heater controll in your cab ?

 

[Bob Beauchaine]

There is another problem that I overlooked - humidity! You indicate that you live in "Tobbaco USA" which is in the SE US - correct? I don't have time to go into this problem because of work but I will post later today.



Bob

 

[Ncostello]

Is it possible as pressure increases the clutch is getting weak? I've saw a 2001 Sebring once do this. It would run cold all day as long as you idled there in the drive. Pull away and it would stop soon after. I guess the clutch could handle it except when you put some rpm load on it.



PS: Is everyone still servicing these systems with R12? Or is it best to just convert to R134A? I've seen switched over systems not cool as well because the evap core isn't really big enough using R134A. At least thats what I was told.

 

[HHhuntitall]

Most are going to 134. It's not the evaporator or condensor that's the problem. It's the expansion valve and the physical qualities of the 134. It's not nearly as effecient as R12, the expansion valve opens a bit too much to properly evaporate the 134, and then the 134 isn't gaseous enough for long enough to cool properly. R12 was designed to run with less head pressure, making the systems last longer.



There are a number of replacements out there, including Freeze 12, FR-12, and several others. Airgas manufactures this: http://www.airgasrefrigerants.com/fr-12.php It seems to work much better, and is designed to work with 134 or R-12 systems. I've only used it twice so far, in older R-12 systems in farm tractors, but the systems seem to work much better.

 

[DVolk]

they still service R12 systems its just exspensive . The whole thing behind the R134 fiascal was because Dupont's patent ran out makeing it legal for any one to manufacture Freon . Ive heard some shops wont use the freezezone id like to learn more from those whom use it as ill be putting ac in my crew cab and dont really like 134

 

[cerberusiam]

If all else fails, propane works quit well in an R12 system. Just have to build the connector to the manifold.

 

[Bob Beauchaine]

In areas of high humidity it's not unusual to see evaporators ice up and cause A/C cooling problems. In addition you might have a heater box that needs cleaning. What I and many others have done is to cut a 4"X4" hole in the heater box inside the cab. Cut it about 4" from the grid in the heater box - the grid next to the passanger side kick panel. You can then clean out the heater box and improve air flow. After you are done you can cover the hole with a piece of black plastic or do what I did - use clear plastic and you can see the evaporator and see if it is icing up or when it will need cleaning. Just be careful of how deep you cut - the further you get from the grid located next to the kick panel. In addition I would make sure the heater box drain is open.



With high humidity you may find that this is a recuring problem but the above should help.



Bob

 

[DVolk]

My dad once said you can use propane as refrigerant except that you have a bomb though

 

[JMDancoe]

Have you put guages on it? If so, what kind of readings are you getting?

 

[Bob Beauchaine]

I ran across this on another web site. It is from Consumer Guide Auto and refers to "Trouble spots" - Air conditioner "The A/C evaporator freezes up because the compressor does not cycle off causing a lack of cooling ('91-'93).



Bob