air con problem

[johnkarl]

I have just done the cylinder head on my m reg 3.0 surf and every thing is going great , but i do have a problem with the air con , as soon as i switch the fan on the air con is engaged , even without the air con button pressed , it is as if it is switched on permanent, when the heater control is set to cold it is freezing as it should be, but the air con clutch is engaged all the time , i was wondering if anyone else has had this problem.I have just changed the heater control unit , but it has not cured the problem any help would be gratefully accepted, thanks--- Karl

[POPEYE]

I was going to say sticking push button on the controll but as ya changed it??? sure the wireing was reconnected ok,?

[johnkarl]

All wires are connected correctly, the only way to stop it working is to remove the single wire that is actually on the unit itself, but thanks for your input, has any of you electrical boffins out there got any idea what might be causing this problem, as it is quite embarrassing having to lift up the bonnet to switch on the air con , thanks again ---Karl

[nero279]

there's a spare wire behind the battery on most trucks with the same connector on as the one on the aircon wire, just wondering if these might have got mixed up somehow? Though i don't think this wire should normally have +12v on it which would be what should engage the aircon.

[johnkarl]

no im afraid it is the correct wire, as, when i turn the fan off, the air con compressor stops, its a strange problem, but i would like to find out why, as it is increasing the fuel consumption, and no one wants that--thanks Karl

[NiftyNev]

You may have a dodgy air con switch and contacts are remaining closed. Maybe the switch contacts are welded together and not switching off or something is broken and not allowing the contacts to open. The switch is very small and delicate and different to all the others on the vent control.

Nev

[johnkarl]

thanks for that , but if this was the case, would not the air con indicator light be on permanently, and would not switch of when switch was depressed, on mine, the light goes on and off as i should, and this is the second heater control fitted, with the same fault[if it is the heater control] and as i have not seen any of the same faults on our web site, i find that having two switches with the same almost unheard of problem, is very unlikely, but again i appreciate your input, and opinion, thanks ---Karl

[Slugsie]

Just been out and checked mine. When the fan goes off, so does the air-con light. Never knew it did that!

So, looks like a dodgy switch/contact somewhere.

[gwyn]

sticky clutch thing

I should imagine that the fed to the clutch is a single feed from the switch as only medium amps need to bring the clutch if not it must go via a relay in which case you need to check out your bank of relays?
Any help?

[johnkarl]

a lot of help , can you direct me to the relays , and when i find them how will i tell if they are at fault, will they have a burnt smell or do i have to open them up and check visually, is this a common fault or is this a one off , i know this is a lot of questions to fire back at you , but i like to know exactly where and how to find the problem , plus if any other of our members have this problem they will be able to go straight to this relay or relays[if it is the relays] and check themselves, saving time and money , which can only be a good thing thanks again for your input and i do appreciate it--Karl

[NiftyNev]

There is a relay on Evaporator Housing but I have no idea if this is for the compressor or how to check it.

Nev

[NiftyNev]

You can see the relay top left of first and second pic and top right of third pic here -

http://www.toyotasurf.asn.au/techsit...npictorial.htm

Nev

[johnkarl]

Thanks again for all your help , it is raining cats and dogs outside and so i will have a look tomorrow, but once again your help is gratefully accepted-- thanks Karl

[gwyn]

BY the way somebody mentioned that the A/C went off at the same time as the fan well this is correct on ALL cars as it would ice-up the evaporator if the fan stopped and the A/C kept running.
Good luck and don’t forget to put your out come on the web as it might help somebody else in the future.

[johnkarl]

Now theres a thing ,i don't think my air con fan works with the commpressor running ,will check later today , as well as look at the relays--Karl