1998 GU Air Conditioner occasionaly does not Work

[Bob]

When it works it works well however every now and then it gets warm and you have to turn it on and off a few times to get it working again.

I tend to think it is a faulty thermostat however cant find one.

Does anyone know if there is a thermostat and where is it ??

[threedogs]

You could swap your air con relay to test,
the one circled is the ECM, anyone you can swap for test purposes

[MudRunnerTD]

Is your engine getting hot? There is a sensor in the bottom of the radiator which turns the aircon off when it senses the engine temp is becoming critical. This may be faulty. Do you have a aircon Thermo fan fitted?

[Bob]

Is your engine getting hot? There is a sensor in the bottom of the radiator which turns the aircon off when it senses the engine temp is becoming critical. This may be faulty. Do you have a aircon Thermo fan fitted?

No Motor was at normal temps and I have two Thermo Fans fitted and both cutting in when required.
Will check the Sensor. Thanks

EDIT

Just found the Sensor at the bottom of the Radiator with it not plugged into anything. Cant see anywhere it could plug into.
Mystery.

[jff45]

Bob, isn't yours a TB45E? If so, the ECU controls the A/C cutout using the engine temp sensor.

The A/C relay is behind the battery. It's marked on the cover

[Chubba]

Bob I don't now how long you have had your 98 patrol but I have had experience with three very early tb45e GUs
One being mine one being my brother's which he doesn't have anymore and a mate who had one a few years ago. All had their AC drop out regularly. I replaced the condenser and upgraded the fan with limited success. The others both upgraded to later models and no problems. I don't have any evidence for this other than anecdotal but I think the early GU tb45e just didn't have a good enough AC. Maybe we shuold put a poll up asking all '98, '99 tb45e what they think of there AC.

[Bob]

Bob I don't now how long you have had your 98 patrol but I have had experience with three very early tb45e GUs
One being mine one being my brother's which he doesn't have anymore and a mate who had one a few years ago. All had their AC drop out regularly. I replaced the condenser and upgraded the fan with limited success. The others both upgraded to later models and no problems. I don't have any evidence for this other than anecdotal but I think the early GU tb45e just didn't have a good enough AC. Maybe we shuold put a poll up asking all '98, '99 tb45e what they think of there AC.

Thanks for the input however up until about three weeks ago the A/c was working perfectly on very Hot Days.
It now works most of the time but every now and then cuts out. I might be wrong but the Compressor still chucks out good cold air so I tend to think that some sensor is the reason.

[Chubba]

Well that's me out then. Lol

[nissannewby]

You could have an ever so slight leak and the gas pressure is a little low causing it to freeze up. The betwee you switching it on and off it may come good. Very easy to get the gas pressures checked.

[Yendor]

If the A/C compressor clutch is still engaged but the A/C stops blowing cold air it's more then likely a problem with the TX valve or H block valve what ever is fitted.

What does your scan tool show the engine temperature as when the A/C stops getting cold?

The GU's run an electronic thermostat for the A/C.

[Bob]

You could swap your air con relay to test,
the one circled is the ECM, anyone you can swap for test purposes


Bob, isn't yours a TB45E? If so, the ECU controls the A/C cutout using the engine temp sensor.

The A/C relay is behind the battery. It's marked on the cover

Relay swapped out and so far so good.

Thanks for the Input guys