hilux 2003 fault

Submitted: Sunday, Oct 27, 2013 at 19:59
ThreadID: 104888 Views:2570 Replies:9 FollowUps:1
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G'day, my 2003 hilux aircon works fine around town but once we hit the highway it has a tendency to blow warm air at high speed, if we pull up and wait for a couple of minutes it starts to work again, have checked over mechanical parts and can hear vents open and close when we work the
the levers and the clutch drops in and out when we switch it off and on, is it electrical or mechanical??? , any ideas???
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Reply By: Member - John - Sunday, Oct 27, 2013 at 20:22

Sunday, Oct 27, 2013 at 20:22
Phil, maybe a faulty high temp switch that is switching off the a/c when you increase the load on the cooling system, maybe not. I am sure other more knowledgable on here will offer plenty of other possible causes. Good luck
John and Jan

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Reply By: PhilG42 - Sunday, Oct 27, 2013 at 20:37

Sunday, Oct 27, 2013 at 20:37
cheers John, had considered that option but didn't want to buy one to check
and here in Port Hedland it's a couple of weeks wait for one of the few who can
test for me,
thank you
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Reply By: Ross M - Sunday, Oct 27, 2013 at 20:43

Sunday, Oct 27, 2013 at 20:43
It may be the aircon has a full load of gas, has it ever been recharged? and the pressure in the system is getting too high when underbonnet temps get up high. The high pressure switch which is beside the low pressure switch in one of the aluminium pipes, may be going open when at the higher speed/underbonnet temp.

Maybe the radiator cooling fan clutch isn't as good as it should be and airflow isn't great under there.
It can be checked if that is happening by adding a thin wire to the aircon clutch wire and fitting a small test light to negative on the end of it. Light will be on when aircon clutch is driving the compressor. If it goes of for extended periods and you are getting warm, then it is an indication of over pressure because of the temp.
If it has been regassed, the service person may have put a tad too much gas in there and it manifests itself when the heat rises.

I'm not aware of anything which would intermittently cut the compressor out.

If it was a aircon clutch drive problem , it would have fried itself by now.
That is my theory. Some checking with the light may reveal the fault.

The high pressure switch is the one which has a definite connection across its terminals when the loom plug is removed, when engine is off. This goes open when too much pressure happens.

The low pressure switch will have no connection across it's pins when plug is off for a test.
Are all the grass seeds out of the rad and aircon condenser?
Ross M
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Follow Up By: Member - LeighW - Sunday, Oct 27, 2013 at 21:03

Sunday, Oct 27, 2013 at 21:03
A lot of strange faults with Toyota air conditioning have been attributed to the air conditioning relay in the main fuse box in the engine bay. If possible swap with a similar relay in the fuse box if there is one to eliminate it.


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Reply By: River Swaggie - Sunday, Oct 27, 2013 at 21:10

Sunday, Oct 27, 2013 at 21:10
Ok in between the air condensor and the front of the radiator collects a lot of dust, leaves etc, looking from the top you'll see a step of black foam , pull it out, get a compressor with an air hose and blow all the crap out. If it hasn't been done for a long time and its full of crap and the gas is fine you'll notice the difference straightaway.

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Reply By: Member - fawkesp - Sunday, Oct 27, 2013 at 21:28

Sunday, Oct 27, 2013 at 21:28

I had a Falcon once that had a similar problem - it turned out to be the a/c radiator unit in the dash (not sure what it is called) where the air passes through and is cooled by the refrigerant. It would freeze up and block the air so it could not pass through.

Turn it off for a few minutes, the ice would thaw, and we would have cold air again.

It turns out the thermostat was set too low, a simple adjustment by the a/c guru and all was well.

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Reply By: olcoolone - Sunday, Oct 27, 2013 at 22:31

Sunday, Oct 27, 2013 at 22:31
Why don't you check the heater tap and see if it is closing off properly and not bleeding through, a little heat from the heater core can knock the edge of the air con.

Around town your engine might only be running at 70 DegC but on the highway at higher speed and more load it might creep up to 85 DegC...... 15 DegC more in the heater core might be enough to blend hot air with the cold air taking the edge off the cold air.

I would suggest taking it to someone GOOD who does auto air con.
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Reply By: Member - Terry W3 - Monday, Oct 28, 2013 at 00:09

Monday, Oct 28, 2013 at 00:09
Phil take it to TLS in at Port mate, see Troy the boss. Washo
AnswerID: 520484

Reply By: Stevesub1 - Monday, Oct 28, 2013 at 08:32

Monday, Oct 28, 2013 at 08:32
If your trips around town are short and the open road, the trips are longer, there could be a problem with the TX valve where you will get cold air for a while, then it will gradually warm. A good vehicle air con shop will find it and replace it which is what we did a couple of years ago.
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Reply By: PhilG42 - Monday, Oct 28, 2013 at 18:31

Monday, Oct 28, 2013 at 18:31
G'day all,
thanks for the tips everyone

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