BJ74 A/C repair, help needed

[jblueridge]

I knew the a/c did not work but I took a closer look today.
With heating/cooling controls set to a/c and very cold, the a/c compressor clutch does not get actuated; pulley spins freely as if a/c was not called for.

What is my next step?

 

[Behemoth60]

I am about to embark on fixing this exact problem on my BJ74 this weekend!

Step 1: Check all your fuses. Maybe look at the electrical diagram. or the FSM. Like you, I've skipped this step, and I am winging it.

Step 2: With all your fuses good, and the engine running, and the fan on (it has to be on!), slowly turn the AC setting knob from off to full, listening carefully for the relay behind the clock in the dashboard to click on at some point. There is a temperature sensor somewhere, and the A/C control relay makes an audible click when it calls for more cold. I have done this already, and I get the click on my truck.

Step 3: With the click verified, look at the A/C clutch to see if it's engaged and spinning. Mine does not. It's likely the clutch, or some problem getting power to the clutch.

Step 4: With the A/C relay on, disconnect the power wire that leads to the clutch, and test that you are getting 24V to that. Make sure the connection is good and secure. Not sure if the engine needs to be running. Maybe go back to step 1 and look at those diagrams and the FSM. This what I am doing this weekend.

Step 5: If there is power to the Clutch, and it is still not turning, replace the clutch with the spare from your parts rig. Oh, step 0.1 Buy a parts rig. Forgot that part. I have a parts rig that had a workign A/C.

At least, that's my plan.

 

[cruiserdan]

Also if the refrigerant charge is too low the compressor will not cycle.

If the compressor cycles and there is insufficient cooling the charge could still be be low (but enough to let the compressor run) or the expansion valve is malfuncto.

 

[jblueridge]

Thank you Sirs!
Behemoth, fuses are next on the list.

Dan: "compressor will not cycle" is the same as the clutch won't kick in? Do you mean fill in with refrigerant and see if it works?

 

[Behemoth60]

if the refrigerant charge is too low the compressor will not cycle.

For clairty... if I have no refrigerant, the compressor clutch will not engage?

 

[Gun Runner 5]

I had the same symptoms on my BJ74. The previous owner had not used the A/C in quite a while. A freon recharge along with a couple of cans of "stop leak" and I was good to go.

 

[cruiserdan]

For clairty... if I have no refrigerant, the compressor clutch will not engage?

Correct.

 

[jblueridge]

Well.... thanks for stopping me in my tracks.

 

[Behemoth60]

Checked.... No nothing in my system. New plan.... Add Refrigerant. Enjoy cool breeze

 

[cruiserdan]

Thank you Sirs!
Behemoth, fuses are next on the list.

Dan: "compressor will not cycle" is the same as the clutch won't kick in? Do you mean fill in with refrigerant and see if it works?

If the system is empty it will need to be evacuated and recharged. If the major components (compressor, evaporator, expansion valve, condenser) are intact it should function. Of course there is a leak of some kind present and depending upon how fast it leaks back out, that will need to be chased down and fixed.

 

[Gun Runner 5]

Checked.... No nothing in my system. New plan.... Add Refrigerant. Enjoy cool breeze

WHAT HE SAID ^^^^^^ plus a Word of caution:
If your A/C hasn't been used in a while there is a good chance the seals will be dry and the refrigerant might leak out. (Quickly or over time). The lubricants in most "stop leak" products will help with this issue assuming the seals aren't totally gone.

 

[Oldtoy74]

My AC issue was the magnetic clutch had burnt out, a local auto sparkle rewound the coil, happy days, living the cool life.

 

[ozcrusier]

My AC is not working so a big thanks for the thread. Oldtoy if my magnetic clutch is not working I may need your sparky's number if I can't get it done local.

 

[jblueridge]

To evacuate and/or recharge the system: threads on fittings for JDM BJ74 are the same as on this sort of USA refrigerant kit?

 

[Oldtoy74]

My AC is not working so a big thanks for the thread. Oldtoy if my magnetic clutch is not working I may need your sparky's number if I can't get it done local.

No worries mate, just give me holla

 

[ozcrusier]

I ran a hot wire today to the pump and the clutch is working fine so it must be low on gas. Thanks for the offer mate.

 

[JuanJ]

Hello,

Pump the clutch full of grease when you're done repairing.

Although it is not in the manual, grease seems to help making it work better.





Juan

 

[peterb]

The receiver/dryer for your truck is available at a USA dealership for @ $20.

 

[jblueridge]

Receiver part number?

 

[peterb]

Looks like it was 88470-14010 but it was $50.30. Sorry, any part under a $100 I really don't pay attention to. Ah - life was so much simpler when I just had a 40. <smile>
Good luck
Peter