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The mkiv Supra Owners Club

Inevitable Summer Time Air-Con Woes


jot_ie

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So, been having a fabulous few days of 25 degrees and over, not complaining, it doesn't happen very often and I do love the summertime.

But getting into a car with leather seat inserts that must be close to 40+ degrees aint funny anymore.

And when I actually need it on these rare occasions here in Ireland, the air con doesn't work.

 

It could do with a re-gas, not a problem, but for the moment the compressor clutch isn't engaging

So I tried all the tests.

 

Check fuses:-

No 2 in the footwell - good

No 17 in the footwell - good

 

Engage compressor clutch:-

no 42 in the engine bay - good. tried crossing this.

mg clt relay in the engine bay - good. Swapped this with the fog relay, that I knew was working. (And vise versa)

 

Whats next?

 

Melting here!!!

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what part of Ireland are you in. Im over with the misses and her little one visiting her mum, she lives 10-20mins from Belfast airport :).

 

Have you tried hitting it with the technical hammer?

The unit could be bad?

 

Hi.

 

Yeah, tried the "russian spanner" approach. Gave it a few smacks with the engine off first, just in case it had seized a bit. Then with the engine running and air con on.

No luck.

 

I'm miles away from you I'm afraid.

I am in West Wicklow.

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Your clutch won't engage if the system is very low on refrigerant. It doesn't take a high pressure to overcome the low pressure cut off which disengages the clutch, usually around 5psi to 9psi on the suction side and a standing system should be 50psi-70psi. The LP cut off is designed to prevent the compressor from pulling a vacuum on the inlet side which will draw in air a moisture through the hoses. To check your gas level easily you need to couple a pressure gauge into the LP service port.

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Your clutch won't engage if the system is very low on refrigerant. It doesn't take a high pressure to overcome the low pressure cut off which disengages the clutch, usually around 5psi to 9psi on the suction side and a standing system should be 50psi-70psi. The LP cut off is designed to prevent the compressor from pulling a vacuum on the inlet side which will draw in air a moisture through the hoses. To check your gas level easily you need to couple a pressure gauge into the LP service port.

 

It probably does need a top up or better still a full re-charge.

But before doing that I am trying to see if the compressor clutch is gone, as I will have to discharge the system in order to fix it.

Just need to try to force the clutch to engage as proof it's working.

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this tells you how to do it and explains the codes....

 

http://www.jack-frost.co.uk/toyota_supra_air_con.html

 

Did that yesterday. got error code no 3. normal.

 

Just found the cooling service manual.

Describes a way to check the clutch.

Lead from the battery positive + to terminal 4 on the connector. Lead from battery negative - to the compressor body.

If the clutch engages compressor is fine and system probably just needs a re-charge.

If it doesn't then the compressor needs a new clutch.

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I'm in the process of trying to sort mine out.

 

Compressor works and I had pressure in the system, so I've just ordered a new dryer and expansion valve hoping after I have changed these and get it re-gased it should be ok fingers crossed!

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I'm in the process of trying to sort mine out.

 

Compressor works and I had pressure in the system, so I've just ordered a new dryer and expansion valve hoping after I have changed these and get it re-gased it should be ok fingers crossed!

 

Its a real pain in the ass for sure. Don't need the thing most days of the year here.

As mine is a daily, I use it for going to meetings etc.. Turning up in a room full of suits looking like a drowned rat isn't my best look :)

Wait till you see, soon as it's fixed it will rain for the rest of the summer.

 

 

Anyway.

Did the tests, resistance across terminals 1 and 2 188 ohms. Specs are between 160-220. Spot on.

Jump the clutch from the battery via terminal 4, it engages. Happy days.

Just need to check the female connector and make sure power is getting that far.

 

I'm hoping its just a low charge pressure now.

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