75 series air con

[Dane]

I was recently in northern Victoria towing my 1800kg ski boat with my HZJ75 on a 40+ degree day on the highway. The engine temp seemed to be same as always but the air con cut out a few times. At first it was far apart and then got more regular. I tried making the thermostat click on and off by turning the controller up and down but it seemed not to have any power (when it had cut out). It just went off for a couple of minutes at a time and then came back on, operating as well as normal. It has been fine ever since that day but I am curious to know if it is normal for them or whether I need to get it looked at.

Thanks.

[mule75]

they have a temp sensor in the side of the block sort of near the inj pump. the wires can break on the end of the sensor.

[roblrc]

If it is a R134a system there is a high pressure switch as well as a low pressure to protect the ac compressor. On high ambient temperature days the compressor head pressure will be higher so the switch cuts power to the compressor if it gets to high.

[Dane]

Thanks Mule75, I will check that out.

roblrc - That makes sense , I suspected it may have been a HP cutout as when it was working, cooling was very good as normal. Does this indicate a problem, or is it to be expected under those conditions?

[roblrc]

Could indicate the system is overcharged or the condensor could be blocked by bugs or mud reducing airflow. This was a common problem with high head pressures mainly in Qld when R134a was introduced caused by high temp and humidity. The manufacturers fixed the problem by fitting the high pressure switch. You could try some of the alternative refrigerant gases based on LPG to lower the head pressure and at a lower charge with more effeceincy.