No Cold Ac...

[Tim Watts]

... in fact, no AC at all!

The AC has not worked since I got the car last December. Wasn't too worried but we've had a few hot days with rain recently and it gets warm in there so it would be good to have it working. Moving the dial to NORM AC or MAX AC doesn't really do anything, although on the MAX AC setting you can hear something moving inside the vents.

Been to the local Halfords this morning for them to do a "check" on the system. They've plugged their test thingy on it - low gas so that was a good start and could explain why nothing was happening.

They plugged the re-gas unit in and the meter went straight to "WARNING" and she wouldn't take anything in.

Suspicion is the clutch is not engaging. Is this an easy check for me?

Is there anything else I could be checking as well - fuses / relays etc?

The fan and heater do work Ok (so ambient cool air and heat are fine).

Thanks in advance.

TMW

 

[Noobz347]

... in fact, no AC at all!

The AC has not worked since I got the car last December. Wasn't too worried but we've had a few hot days with rain recently and it gets warm in there so it would be good to have it working. Moving the dial to NORM AC or MAX AC doesn't really do anything, although on the MAX AC setting you can hear something moving inside the vents.

Been to the local Halfords this morning for them to do a "check" on the system. They've plugged their test thingy on it - low gas so that was a good start and could explain why nothing was happening.

They plugged the re-gas unit in and the meter went straight to "WARNING" and she wouldn't take anything in.

Suspicion is the clutch is not engaging. Is this an easy check for me?

Is there anything else I could be checking as well - fuses / relays etc?

The fan and heater do work Ok (so ambient cool air and heat are fine).

Thanks in advance.

TMW

I don't understand... If they were diagnosing the system, why didn't they finish?


If the freon level is low, the clutch won't kick on. That's the purpose of the low pressure switch.

That system sounds like it's been sitting for a while. It needs to be sucked down, new oil added, pressurized then checked for leaks by a professional auto A/C service tech.

The possibility exists that the A/C pump is seized. If so, source a replacement. This is something the A/C tech would be able to determine in no time.

There are only a limited number of things that you do on your own. A/C requires some pretty specific tools.


To check if the A/C clutch is engaging:

Pull the plug from the switch located on the A/C accumulator (this is in the engine bay and looks a small pressure tank)
Start the motor
Set A/C to MAX
Short the pins on the plug and check for clutch engagement and compressor movement

If you get rotation:
Accumulator is low or switch is bad

If the motor dies or the belt squeals:
The compressor is seized

If the motor rpm momentarily reduces then recovers and the compressor rotates normally without noise:
It needs to be charged and checked for leaks.


If you hear the clutch engage and the compressor spins momentarily, or not at all, but clicks freely:
A/C clutch is bad

@jrichker may have more troubleshooting checks for your 95/96

Do you have any butchered wiring in the engine bay or beneath the dash?

 

[Tim Watts]

Hi, and thanks for the reply.

Halfords are a generic car parts / supplies store you get in retail parks - whilst they are good for some parts and services, the Air-Con service they offer is basically does the system have gas and if not can we re-gas it - that's it. It's cheap and cheerful, but as the initial diag is free it was worth doing - if the regas was then going to work and get it going again it would only have cost me £30 so can't complain.

Thanks for the pointers - will have a play later and have now found a place about a mile away that say they can action diagnostics and repair so am also going to pop in later and have a chat with them just to get a vibe from them.

Regards

Tim Watts

 

[Noobz347]

basically does the system have gas and if not can we re-gas it

Hiya. Don't ever let any of these hacks touch your car again. Generally, parts store clerks are qualified to operate cash registers. "Adding" another can of coolant (usually contains oil) on-top the oil and coolant already in the car, leads to LESS coolant and MORE oil than what is supposed to be in the system. They do not have the tools or knowledge to service ANY A/C system. Do not use off the shelf coolant/oil recharge cans.

Too much oil and the compressor sends the whole thing through the system until something breaks. Often, it's the compressor itself.

 

[Tim Watts]

Hi.

Don't worry - I only wanted them to confirm gas status.

She's booked in tomorrow afternoon somewhere else for a proper diagnosis. £35 but should get an answer from it.

TMW

 

[Tim Watts]

She's booked in tomorrow afternoon somewhere else for a proper diagnosis. £35 but should get an answer from it.

It's the compressor

We have power to it but it doesn't do anything.

I shan't worry about it now - it's Autumn now so a project for the Spring...

TMW

 

[Noobz347]

It's the compressor

We have power to it but it doesn't do anything.

I shan't worry about it now - it's Autumn now so a project for the Spring...

TMW

Probably the easiest thing to swap. This is not bad news.

 

[Randymo]

I have a 98 Mustang I have no cold a/c and when I took it in they said it was the constant control relay module

 

[wmburns]

Test for +12 volts with the key on and AC on at the low pressure switch Purple wire. Use a KNOWN good ground.

IF NO power:

• Check for blown fuse
• AC mode control switch is not in the AC position.
• Wiring fault between the AC low pressure switch and the AC mode controller

IF power: THEN more tests are needed to rule in/out a CCRM problem. But one of the lowest tech methods is to inject +12 volts to the AC clutch coil. If it pulls up, this proves that the AC clutch is good.