Intermittent A/C operation

[Wagoneer300te]

I have this weird thing going on with my A/C. Works great in the morning, but at 90+ degrees it seems to quit. Sometimes while you drive, but usually after restart. My Autologic tester only tells me compressor clutch blocked and ECU box temp. exceeded. I swapped the general module and it seemed to work for a little while, but its back to not working. Anybody have these symptoms?

 

[gsxr]

Year/model of your car? (Since your forum handle includes "300TE".)

LOTS of things to check here. Verify the twin electric fans work on low speed when you short the leads on the red pressure switch at the drier, and when the AC dies in the afternoon, try shorting the pressure switch to see if that makes the compressor turn on or not.

The "clutch blocked" fault code is indicating a difference between engine RPM and compressor RPM. This could be a belt slipping, or compressor speed sensor issue, or other compressor issues.

Do you have manifold gauges to connect so you can view low & high pressures in the system? It will be difficult to diagnose without that data, if it doesn't turn out to be something simple like a loose belt.

 

[gerryvz]

Check this thread for some ideas on diagnosis. I had a situation where I had intermittent A/C operation. You need to take a methodical approach to testing each of the key components in the system:

• pushbutton unit (PBU) in the dashboard
• pressure switch at the receiver-drier
• temperature switch at the receiver-drier
• clutch operation
• fan operation (both high speed and low-speed) -- also fan-related fuses and relays

[SOLVED] A/C Compressor not working -- tracking down the cause | Heating and Cooling (Interior HVAC systems)

Following up on my Top-End Rebuild thread, I have driven the car around 1,700 miles since completing the job last September-ish. I have only had one problem that I've noted since I completed the job -- the A/C compressor through the fall/winter/spring has been sort of hesitant to come on. It...

www.500eboard.co

 

[gerryvz]

As the @gsxr said, you really should connect a set of A/C manifold gauges so that you can see the pressures in your system. Being a 300TE (per your user name), is it R-12 or R-134a (what is the year of the car)? Each refrigerant has different system pressures. You said you replaced the GM/BM ... so this makes me scratch my head and think maybe you have a 500E or a 400E?

Also, it may be something as simple as not having enough refrigerant in the system to keep things running. That's why the gauges can help eliminate (or identify) low refrigerant as a cause.

I got the same "clutch blocked" code on my E500 per the above thread. You may also want to check the electrical connection (three wires) on the top of the compressor, to ensure that there is integrity and that an electrical signal to fire the compressor and engage the clutch indeed is received.

 

[emerydc8]

Check this thread for some ideas on diagnosis. I had a situation where I had intermittent A/C operation. You need to take a methodical approach to testing each of the key components in the system:

• pushbutton unit (PBU) in the dashboard
• pressure switch at the receiver-drier
• temperature switch at the receiver-drier
• clutch operation
• fan operation (both high speed and low-speed) -- also fan-related fuses and relays

[SOLVED] A/C Compressor not working -- tracking down the cause | Heating and Cooling (Interior HVAC systems)

Following up on my Top-End Rebuild thread, I have driven the car around 1,700 miles since completing the job last September-ish. I have only had one problem that I've noted since I completed the job -- the A/C compressor through the fall/winter/spring has been sort of hesitant to come on. It...

www.500eboard.co

As a last component test, swap out the base module. It has been known to cause intermittent a/c,, but definitely check the others on Gerry's list first, unless you happen to have a spare BM to swap.

 

[gerryvz]

As a last component test, swap out the base module. It has been known to cause intermittent a/c,,but definitely check the others on Gerry's list first, unless you happen to have a spare BM to swap.

I think he did say that in his first post, that he swapped out the GM (aka BM).

 

[emerydc8]

I think he did say that in his first post, that he swapped out the GM (aka BM).

Aah. General Module = Base Module.