The AC in my TS keeps turning itself on an off.

The owners manual says it should do this when in "econo" mode but implies that when in "AC" mode the ac should just stay on all the time. However, when i run it in AC mode it still cuts in and out all the time.

About a year ago I had the system looked at and they replaced the receiver/drier but this did no help.

It's an annoying issue because each time it switches the engine revs spike up and drop down making it difficult to drive smoothly.

In my old TR the AC stayed full on when in "AC" mode.

It seems to me like the switching might be wired up wrongly or something? I changed the relay in the fuse box in the engine bay but this did not help either.

Apart from this the system does pump a lot on nice cold air so I don't think it's a gas problem.

Does anyone have any ideas? It gives me the %^&*s

This is quite normal for the compressor to cut in and out, there is a thermostat bulb in the receiver box and when the air going into the unit drops to a certain temp the aircon compressor turns off.

It does it about every 60 seconds even in "AC" mode. Is that a normal rate? Bloody annoying.

Could it be disconected so It's just on all the time?

Why don't you just turn it to 'snowflake' mode..... then it stays on all the time. Econo mode is designed to cut in and out.

I should have made it clearer. I run the AC in "AC" mode all the time, but it still cuts in and out just like it was in "econo" mode.

Ahhhhhhhh, maybe it's the control then.....

I have one here if you want it. Got a little bit of wear and tear. Should have asked me before I sent you those indicators hey

Ahhhhhhhh, maybe it's the control then.....

I have one here if you want it. Got a little bit of wear and tear. Should have asked me before I sent you those indicators hey


Where's the contol unit situated? In the dash?

...those indicators make my car look awesome.

Glad you like them..... no i mean the actual climate control unit that is in the front of your dashboard.....

No climate control in this car. Just bog standard AC.

well,it is possible to rig the thermostat so it never cuts the compressor out,but is useless cos it freezes the lines etc,they need to cut in and out to stop this

Oh, I was afraid of that. maybe it something else wrong with the car that make me feel the variation in engine revs so much?

Your revs should pick up a slight amout when it cuts in. Perhaps your stepper motor is not working correctly

I will do a test after work to see how much my revs are jumping when the compressor cuts in. I can feel it when am driving.

Ok, sitting in the driveway the idle speed with the ac on varies from 750 -900 (when the compressor switches on) Seems pretty normal. Go for a drive however and the idle speed can go up as far as 1800rpm. Pulling up at lights stop signs etc more often that not the idle speed stays up at 1800 for a few seconds before dropping back to about normal. Pretty much anytime I come to a stop with my foot on the clutch the engine is hovering at 1600-1800 rpm.


That can't be right?

Oh, If I turn the aircon off everything behaves itself.

ok have a similar prob with my ac. I always run in econ mode which only cuts the compressor when not required and i never notice it doing this, it deffinitley doesnt do it after a few seconds or minutes.
If it is like mine it is triping on head pressure this was proven by tipping a water over the condenser coil which made it stop for a little while till it built up again.
Reason for this could be two things. On top of your reciever (the cylinder with the sight glass on top) is the HP LP sensor. That could be cactus.
The other is that your system has moisture in it, which is absorbed over time through the rubber hoses, moisture mixed with the refrigerant gives high pressures. To fix this you will need to have your system reclaimed and evacuated to dry it out then re-gassed (with clean gas not your used stuff) This is what i am doing before touching the HP LP sensor.
Am i right in thinking that your car runs R12? If so it will not be cheap as this gas costs an absolute fortune these days (unless you know someone with a bottle of it) they stopped production of new R12 a few years back.
Hope this helps.