GU Series III aircon problems

[roverrat]

Guys

Gunna throw this one out to the masses. My Patrol when running in extreme heat conditions, whether it be constant highway running or 4wding, seems to cut out periodically.

For example it was around 42 two days ago on a trip to perth .... overtaking get up to say 130 the aircon switches off .... damn hot with two little kids in the car. Then after about 5 minutes of running at 100-110 it turns itself on again.

Is this a normal thing for a patrol..... the strange thing is the enging temp guage does not 'appeared' to have moved at all!!!!!

This made for an extremely uncomfortable trip for me and my family.

Any ideas???

[weeman]

Guys

Gunna throw this one out to the masses. My Patrol when running in extreme heat conditions, whether it be constant highway running or 4wding, seems to cut out periodically.

For example it was around 42 two days ago on a trip to perth .... overtaking get up to say 130 the aircon switches off .... damn hot with two little kids in the car. Then after about 5 minutes of running at 100-110 it turns itself on again.

Is this a normal thing for a patrol..... the strange thing is the enging temp guage does not 'appeared' to have moved at all!!!!!

This made for an extremely uncomfortable trip for me and my family.

Any ideas???

Yeap there is a solution my mate with a non intercooled version turbo gu had the same problem.

Now there is a switch/fuze in the front that can be hard wired, i have to do the same as i removed my aircon fan.

I will hopefully speak to my mate soon and find out where the switch/fuze area is however its safe to do so as he has done on his gu for a while now.

[roverrat]

thanks weeman its bloody annoying, i was thinking it was some kind of thermal overload switch cause it can be 60 degrees outside but at idle it works fine (the aircon) but as i said under load it decides it dont wanna work .......

[purplebus]

not sure about patrol but my mates diesel 80 series cuts out but only if it is REALLY hot. apparently its a safety feature from toyota and they said it could be bypassed. may be worth a call to nissan, they may have a similiar setup and it may be cutting out to early. does the ac fan come on when the a/c compressor kicks in..??
Maybe worth checking your temp gauge is ok as well.

[weeman]

its just a cut out switch for the aircon its quite silly and mainly occured on the non intercooler gu's krimnl had the same issue on his after he fitted a front mount....

[roverrat]

so this is a 'normal' thing bearing in mind i have a m12000 and 2 hella 4000's blocking the front area behind the aircon radiator?

is there any issue cutting this magic switch out? I mean what could the possible downside be??.... freezing the lines? it couldnt possibly over heat the motor?

[chimpboy]

It would be the pressure sensor. I would not be inclined override it. I would be more inclined to upgrade the condenser fan with something much beefier.

Not talking GU specifically but most late model A/C systems have two pressure switches, one for over/under pressure which cuts off the compressor if there is a pressure problem, the other to turn on the condenser fan. On a hot day your scenario would be:

1 a/c switched on
2 pressure rises
3 condenser fan kicks in
4 condenser fan is not adequate for the job
5 pressure rises more
6 compressor is cut off for its own protection
7 pressure drops, compressor cuts back in again

I am suggesting fixing the problem at stage 4 rather than stage 6.

[roverrat]

ok jason cheers for that because of where i live and the subsequent temperatures i can see your point ... so maybe install a decent size thermo fan in place of current condensor fan?

If i was still back in vic i would be inclined to just bypass the switch ... but out here .... i think you are making good sense.

[chimpboy]

ok jason cheers for that because of where i live and the subsequent temperatures i can see your point ... so maybe install a decent size thermo fan in place of current condensor fan?

If i was still back in vic i would be inclined to just bypass the switch ... but out here .... i think you are making good sense.

I think you could get away with just bypassing the switch but there is no downside to grabbing a big thermo fan and putting it there instead, other than the price of it; it is only going to help keep everything cool anyway.

[roverrat]

just had another look at it again there is room on the right (drivers side) of the radiator for another same size thermo fan that is currently fitted as stock .... has anyone done this one before as all the mounting bolts etc are there ... will the wiring loom to the OEM thermo run a second one .... say from a wrecker or would the current draw be too much?

[nabstud]

just had another look at it again there is room on the right (drivers side) of the radiator for another same size thermo fan that is currently fitted as stock .... has anyone done this one before as all the mounting bolts etc are there ... will the wiring loom to the OEM thermo run a second one .... say from a wrecker or would the current draw be too much?

My 99 GU manual 4.5 wagon has 2 fans fitted from the factory.



The A/c cutting out has nothing to do with the pressure switch. The A/C has a thermal cutout that turns it off when the engine starts to get a bit warm. It can also turn on the electric fan (when A/C is off) when the temps start to get up a bit.

This is the wiring diagram for a 92 GQ. The GU are similar but have ECU control, this pic shows quite clearly how it works.
Red box show AC thermal cutout (automatic).
Blue box shows why the fan keeps going (automatic and manual). Also shows that the fan can be turned on without the AC being on.

[bj on roids]

Admittedly driving well in excess of indicated speed limits, priceless. Comlaining about aircon cutting out, HTFU

[roverrat]

Admittedly driving well in excess of indicated speed limits, priceless. Comlaining about aircon cutting out, HTFU

when over taking tard ... read the post .. if you have nothing better to add STFU and get the teaspoon of cement you require for your recommended dietry intake ...

[roverrat]

just had another look at it again there is room on the right (drivers side) of the radiator for another same size thermo fan that is currently fitted as stock .... has anyone done this one before as all the mounting bolts etc are there ... will the wiring loom to the OEM thermo run a second one .... say from a wrecker or would the current draw be too much?

My 99 GU manual 4.5 wagon has 2 fans fitted from the factory.



The A/c cutting out has nothing to do with the pressure switch. The A/C has a thermal cutout that turns it off when the engine starts to get a bit warm. It can also turn on the electric fan (when A/C is off) when the temps start to get up a bit.

This is the wiring diagram for a 92 GQ. The GU are similar but have ECU control, this pic shows quite clearly how it works.
Red box show AC thermal cutout (automatic).
Blue box shows why the fan keeps going (automatic and manual). Also shows that the fan can be turned on without the AC being on.

thats utterly fantastic if i had an ecu ................

[roverrat]

Admittedly driving well in excess of indicated speed limits, priceless. Comlaining about aircon cutting out, HTFU

when over taking tard ... read the post .. if you have nothing better to add STFU and get the teaspoon of cement you require for your recommended dietry intake ...

ps bj do you have anything to add to this topic in the way of a resolution? .... tech maybe ...?

if you dont i would appreciate it if you do not contribute anymore to this thread.

[nabstud]

thats utterly fantastic if i had an ecu ................

Ummm, that wiring diagram is from a 1992 diesel GQ, definitely no ECU there! And the parts that I outlined are not electronic, just relays and switches.

[bj on roids]

just had another look at it again there is room on the right (drivers side) of the radiator for another same size thermo fan that is currently fitted as stock .... has anyone done this one before as all the mounting bolts etc are there ... will the wiring loom to the OEM thermo run a second one .... say from a wrecker or would the current draw be too much?

My 99 GU manual 4.5 wagon has 2 fans fitted from the factory.



The A/c cutting out has nothing to do with the pressure switch. The A/C has a thermal cutout that turns it off when the engine starts to get a bit warm. It can also turn on the electric fan (when A/C is off) when the temps start to get up a bit.

This is the wiring diagram for a 92 GQ. The GU are similar but have ECU control, this pic shows quite clearly how it works.
Red box show AC thermal cutout (automatic).
Blue box shows why the fan keeps going (automatic and manual). Also shows that the fan can be turned on without the AC being on.

thats utterly fantastic if i had an ecu ................

[chimpboy]

If the 4.5's came from factory with two fans there, that would probably make getting a second fan seem more like a good option.

[big red]

pressure switch is likely to be cutting it out ... when the heat goes up the pressure goes up .... bypass and you can blow hoses, leak refrigerant through gaskets etc.

just slow down when it turns off

the engine fan would shift a lot more air than an electric fan at speed so an extra electric fan would only be of use at slow speeds and may cause more air restrictions.

i would check and clean radiator fins, condenser fins, fan Hub etc.