A/C Clutch

[97f150]

Hey guys, I havent been using the a/c much as its been cooler here, but I noticed the other day that it didnt seem to be blowing cold. Today I turned it on again and noticed that it wasnt cold. Further investigation shows that the clutch is not engaging. It has 134a in it as the high/cold is equalized from the clutch not cycling. No odd noises, nothing, just not coming on. I can turn the clutch by hand, Ive checked fuses, swapped relays, bumped the clutch by hand and nothing. I replaced the transducer switch as it broke in the diagnostic process, tried to pull the connector off and the whole [censored] thing came apart, so thats replaced. Also the condensor fan is coming on like it should. Im stumped, I dont see any other switches or anything on the lines, no CEL or anything. Anyone ever experience this or hear of this? Thanks.

Truck is an 02 Ram 1500 with 4.7 btw.

 

[Nick R]

If it's below a certain temperature, the A/C won't kick on, to prevent freezing up the coil. Also, if the freon pressure falls below a certain threshold, the compressor won't come on either.

 

[Deltona_Dave]

There may be a relay in the main fuse box under the hood. sometimes they decide to retire.

Dave

 

[mechtech2]

There has to be a minimum static charge to let the clutch engage. Somewhere around 40 lbs at rest is the minimum.

 

[97f150]

Both gauges are showing 115. This brings the low side into the red warning area, I assume because its not circulating the 134, and they are staying equalized. Any preferred procedure for checking power to the compressor?

 

[97f150]

Okay, I have 13.72 volts at the connector going to the compressor with the air wide open. I was unable to "jump" the compressor itself because I dont have the right connectors here for the spade connections. Also, to correct my original post about the pressures being equalized at around 115, I checked again and the high/low side is equalized at 70. Is that too low?

 

[mechtech2]

115 static is way too high!
Unless it is well over 100 F where you are at.
Possibly you checked them when the system was really not at ambient temperatures - it still had residual heat from the engine bay. It did not cool down enough - It think.

 

[97f150]

When I checked yesterday the engine was at full operating temp and had been for 20 minutes or so. The hood was lifted only to check that as I thought I may have lost the charge.
Today the truck had been shut off overnight and only started to check the voltage to the compressor, then I rechecked the charge, it was 70 on both low/high, the engine only ran about 5 minutes with the hood up. The temp when this was done was 68 degrees.

 

[dishdude]

If that truck has an expansion valve, I'd look at that. The pressure shouldn't be equal.

 

[97f150]

Im about to replace the whole shabangle. Compressor, accumulator, and orifice tube.

 

[ComfyShorts]

Originally Posted By: 97f150
Im about to replace the whole shabangle. Compressor, accumulator, and orifice tube.


If your compressor clutch is not engaging you will have the same pressure on both low and high sides because pressure differential occurs when freon is pumped through a restriction, no pumping no differential in pressure. You said you're getting voltage to the compressor clutch coil with AC on...that only leaves 1 possibility since its case ground(on most cars anyway), replace the AC clutch coil and enjoy your AC.

Also sometimes if you don't know what you're doing instead of throwing parts at it you can save some $$$ by taking it to a shop. I know this is BITOG and automotive repair shops are the devil around here but I wouldn't attempt to perform surgery on myself because I once put a bandaid on

 

[SHOZ]

It may be a worn clutch and the coil can't generate enough force to pull it in. On Tauruses it is pretty common with age. But all you need to do is take the pulley off and there is a small shim washer to remove.

With the engine running and the AC is a mode the compressor should be on bump the pulley with a broom stick of something to see if it will pop on and turn the compressor.

 

[97f150]

Originally Posted By: SHOZ

With the engine running and the AC is a mode the compressor should be on bump the pulley with a broom stick of something to see if it will pop on and turn the compressor.


It does not. BUT, I have tried and I dont know how hard I would have to bump it, but I cant give it more then a love tap as angling the stick in any direction in order to give it a better bump will result in it hitting the fan blades.

ComfyShorts, the beauty of forums is learning about stuff. And I didnt search, and beat my head against the wall with this to just turn it over to a shop. If at any point I feel anything is beyond my league (head gaskets for example, I will not touch), it will go to a shop right away. But for stuff I am sure I can handle, I prefer to do myself and learn about it. Whats the worst that can happen? I mess it up, take it to a shop and poke out a bit more, big deal I will still learn what I did wrong and know not to do it next time lol. I dont run from myself.....

 

[artificialist]

Originally Posted By: 97f150
Im about to replace the whole shabangle. Compressor, accumulator, and orifice tube.

Also flush out the system if the compressor gets replaced.

Some of the modern condensers can't be flushed and should be replaced when the compressor fails.

 

[97f150]

Okay so it was the compressor. Apparently the coil went bad, but there is no way to change just the coil, so yesterday I put in a new compressor, accumulator, and liquid line with orifice tube and after a 1.5 hour vacuum and recharge all is well.

 

[Chris142]

Originally Posted By: 97f150
Apparently the coil went bad, but there is no way to change just the coil,
Who told you that?

 

[97f150]

Its the only thing that really makes sense. Power going to the coil, clutch not frozen, not noisy, pulley tight, no trash or shavings or anything else but clean oil when I dumped the oil out. It also does not run when "hot wired". I dont know much about these, is there anything else that would cause my particular condition?

Also, the new one that I ordered from Advance and put on was branded "Factory Air", which I found out is made by 4 Seasons. I know the remans by this company is nick named "for seizing", do I have to worry about a new compressor from them?

 

[Chris142]

Originally Posted By: 97f150

Also, the new one that I ordered from Advance and put on was branded "Factory Air", which I found out is made by 4 Seasons. I know the remans by this company is nick named "for seizing", do I have to worry about a new compressor from them?
4 seasons new stuff is usually made in TX and seems to be ok. It's their rebuilt stuff thats garbage.

Where was your new compressor made?

 

[97f150]

"Factory Air by 4 Seasons" and "Made in USA" is all the sticker and box said. Advance had the rebuilt in stock, but had to order this one. I didn't know it was made by 4 Season until I was about to put it on.

The liquid line with the orifice tube and accumulater was made in China though. Also "Factory Air" so I assume although it doesn't say it, these are made by 4 Seasons as well.