A/C problem

[SShafranko]

When i push my A/C button i noticed that there is no cold air coming out. I walked to the engine bay and noticed that the clutch was not ingaging on the compressor. Where do i start? Is the compressor done? Is there a way to test it? 104 degrees here past couple of days. thanks in advance

 

[Skydiver]

The low pressure "cut out switch" is not allowing your compressor to engage. This switch is on ac systems to prevent an ac system from pulling a vacuum on the low side in case it loses refrigerant. It prevents contaminates from entering the closed system. This is true if all the other electrical systems (fuses mainly) check OK. You should still see the clutch cycle for even a few seconds unless all the refirgerant is lost. In that case you have to find and fix the leak. These systems do not use refrigerant, it leaks out and must be replaced.
Add r-134a for a quick fix. Get a kit or as I did, a nice set of gages.
Make sure your condensor is free from bugs and is very clean.

 

[SShafranko]

Ty i keep my condenser spotless. Is there a fuse for this? I'm going to check now

 

[B.G. Smith]

Before you go to a lot of trouble shooting problems, Try pushing the AC buttion and see if the yellow light comes on, if not try turning the fan to a higher sped and see if it works. The AC comnpressor won't come on unless the fan is running. The resistor for the fan speeds had a bad connection on mine and stopped the AC. bg

 

[SShafranko]

Before you go to a lot of trouble shooting problems, Try pushing the AC buttion and see if the yellow light comes on, if not try turning the fan to a higher sped and see if it works. The AC comnpressor won't come on unless the fan is running. The resistor for the fan speeds had a bad connection on mine and stopped the AC. bg

The yellow light does come on. Where is the resistor plug for the fan speeds?

 

[B.G. Smith]

It is directly below the glove box on bottom of AC housing, some wires going to it and two screws holding it in place. bg

 

[sag2]

Unplug the compressor clutch connector and jump B+ to one side and ground to the other. The clutch should engage. If it does, low pressure cutout (leak), or control problem. If not, time for a new compressor. Clutch is not sold by itself.

 

[TMax]

Mine did the same thing and we replaced the AC compressor. THEN I heard about the transducer that can go out which prevents the compressor from kicking on. I'll look for the thread. The members said this was a common occurance and that when they replaced the stock item with an aftermarket tranducer, the ac worked again. Anyone else know better about this?

 

[B.G. Smith]

https://www.turbodieselregister.com...ns/214559-evaporator-fin-sensor-question.html This might be what you are referring to?? bg

 

[DPrew]

My AC tanked last summer on my 06'. Everything had to be replaced. Thank God for that Business Link warranty. For $100 I got a whole new system.

 

[JeffJackson]

I had the same problem this spring. On the first hot day, the dash light came on, but the compressor didn't kick in. I jumpered across the relay under the hood and verified the clutch was working. I ended up borrowing gauges from a guy and work and found there was no refrigerant in the system. I evacuated the system and checked that it would hold 30 psi vacuum, then refilled it. It's been working fine for 3 months now.



You may just need to add some refrigerant so the ECM will turn on the clutch relay.

 

[SShafranko]

I brought it to a place yesterday and he hooked up the gauges to it. He said that it relly wasn't that low but he put a bit of 134 into it. I went in the truck and pressed the a/c button on and off a few times and it started to work. I left his shop and the a/c was working. He did say that the pressure seems a bit high for some reason. Last night it stopped working again.



If i push the button and run to the engine bay i can see the clutch engage spin a few revolutions and then stop. It does this thre or four times and then stops completely. I am going to bring it to a shop next week i think and let them figure it out. Although i am going to do the jump trick mentioned above and see what happens.



Thanks folks

 

[Skydiver]

Sounds like your low pressure cut out switch is doing its job. This switch prevents the low side from being pulled into a vacuum in the event of refrigerant loss. If you do the jump trick and the leak is on the low side you will pull air and other contaminates into the system.
Did he say if the high pressure was on the high side or the low side?
Your system may allready have some air in it which will cause the high side to spike. Find the leak, fix it, pull a vacuum, let it sit for 2 hours under vacuum, recharge and enjoy.

 

[SShafranko]

Sounds like a plan. I'm gonna bring it in this week. Hopefuly its that simple. Thanks. Ill post the outcome.

 

[Crunch]

Sounds like your low pressure cut out switch is doing its job. This switch prevents the low side from being pulled into a vacuum in the event of refrigerant loss. If you do the jump trick and the leak is on the low side you will pull air and other contaminates into the system.
Did he say if the high pressure was on the high side or the low side?
Your system may allready have some air in it which will cause the high side to spike. Find the leak, fix it, pull a vacuum, let it sit for 2 hours under vacuum, recharge and enjoy.

For those that aren't all that familiar with A/C systems but still want a quick diagnostic tool you can't go wrong with the pressure gauge/dispenser set up for $16. 95 at Walmart. By itself you can use it to check the pressure on the low side. If the pressure reads low, the unit can be used to add R134a. It's a simple, blue trigger handle (like a Windex bottle) with a gauge built in and a hose to connect to the low side connector. Cans of R134a screw on just below the valve. Just don't buy the kit that comes with 3 cans of refrigerant. The R134a that's in the kit has the leak sealer in it. If you're only adding a can or two every few years I have to question the need to spend money searching for, and repairing a leak. And with the flaws in the A/C systems on these trucks there is no guarantee it won't leak somewhere else. The cost of the dispenser and cans of refrigerant over the life of the truck for a tiny leak is going to be far less than a single A/C repair.

 

[SShafranko]

I bought the kit and hooked it up to the low pressure side this weekend and it showed the pressure in the red aroud 100 so i didn't add any. What would cause the pressure to be so high? I gues the sensor shuts the clutch off if the pressure is too high also?

 

[Crunch]

I bought the kit and hooked it up to the low pressure side this weekend and it showed the pressure in the red aroud 100 so i didn't add any. What would cause the pressure to be so high? I gues the sensor shuts the clutch off if the pressure is too high also?

Since the trigger/dispenser only fits the low side connector it eliminates the possibility that you connected to the high side connector. Unfortunately, the Walmart kit/unit will only look at the low pressure side. If you have access to the standard set of gauges the AC/Heater section of the 03DRM. PDF has this:



Symptom: The low side pressure is normal or slightly high, and the high side pressure is too high.



Cause: 1. Condenser air flow restricted. 2. Inoperative cooling fan. 3. Refrigerant system overcharged. 4. Air in the refrigerant system. 5. Engine overheating.



Symptom: The low side pressure is too high, and the high side pressure is too low.



Cause: 1. Accessory drive belt slipping. 2. Fixed orifice tube not installed. 3. Faulty compressor.



I know your truck is a different year, but I bet A/C problems are pretty similar across the board. Hopefully, it's not the compressor.

 

[SShafranko]

Thanks crunch, im not too familiar with the a/c system so i'll leave it up to my mechanic. He is pretty good and i trust him. Thanks again.

 

[Skydiver]

Was the 100 PSI with the engine running/compressor turning? If so that is way too high.
I'm wondering if one of your (high or low) pressure switches is failing.

 

[SShafranko]

UPDATE..... Last week my mechanic (Barry) put some dye into the system. I brought the truck in today and he found that the compressor front seal is leaking. So he is replacing the compressor $380. 00, orifice tube $45. 00, and receiver=drier $100. 00. With labor i'm spending $950. 00. Did not need this right now but what can you do. With 170,000 miles on the clock i guess it was do.



Hopefully this will solve my problems. Thanks everyone for the help.