AC not cold - '90 HDJ81 (1 Viewer)

[shromani]

I have a 1990 HDJ81 which had a good working AC.

What’s the problem?

AC does not blow cold air and the compressor does not turn on. When I engage the AC, all appears correct on the dash, fan comes on and lights on controls are on. But cold air never appears. I noticed the compressor doesn’t come on, if I put 12v to the compressor it will spin but not engage the clutch for the pump.

Tried troubleshooting with FSM but there are so many switches and sensors involved, many far behind the dash, so I am out of my depth. Fuses are good – so I got that going for me.

What has changed:

I had my head gasket done last summer and the AC hasn’t worked since. When I first troubleshot the issues, I notice they forgot to connect the power to the AC Compressor. I should have return to the shop to ask if they forgot anything but didn’t. So now, I have to own this issue. Before I take it to professionals is it possible there’s anything they could have not reconnected that would cause this? Example is while the AC is on, why does the AC compressor does not get 12V unless I supply it myself, and then when I do, it does not engage the pump, so likely there is another sensor in play to switch 12v to that compressor, but where?

I am concerned about the high cost of AC repair, and could live without AC myself, but for the Mrs. to enjoy our summer camping and overlanding, she would greatly appreciate the AC.

Any troubleshooting tips would be appreciated. My hope is I may get lucky and find a loose wire, or disconnected sensor?

 

[Loober]

You said you put 12v directly to the compressor and the clutch did not engage? In some cases there are safety switches where it will not allow the compressor to engage if the system is low on refrigerant, I would check that first.

 

[shromani]

You said you put 12v directly to the compressor and the clutch did not engage? In some cases there are safety switches where it will not allow the compressor to engage if the system is low on refrigerant, I would check that first.

Thanks for the reply. I have tried to look into the glass windows of my refrigerant and cannot seem to see anything significant. Can I tell visually or do I need special equipment?

 

[roscoFJ73]

Most likely they let all the refrigerant gas out. If it was working ok before you will probably be up for a regas and probably new orings, its not expensive.

 

[Douglas S]

If you applied 12v directly to the compressor clutch and it didn't engage then there's definitely an issue with the compressor clutch.

Applying 12v directly bypasses any kind of logic built into the system.

 

[shromani]

Hello, just to follow up on my post. Had my AC serviced by EBI and they replaced my O-Rings on the compressor, the Dryer and recharged my system. Cool air again and my co-pilot (the Mrs.) Is happy. It appears the 28 yo AC owed no favours and not a DIY fix for me.