Hi! Firstly, why does the a/c only ever play up when the weather's hot?!?

I have 1996 MY 855 with ECC.

Changed my evaporator last August (5,000 miles ago), system been perfect, and used 99% of the time when car driven since then.

Few weeks ago, the A/C and REC lights flashed, on and off for a week or so. I can't/didnt get codes read via OBD2.

A/C still fine and cold (which is all I'm really interested in!).

BUT, last week while driving the cold air coming out the vents went warmish with faint smell! Really p@**%d off! Shut it down, tried 10 mins later and it was ok. Then it happened again - 10 mins later was ok. The guy who re-gassed ot last year came back, no leaks found (dye was put i last time) so he re-gassed, and all seemed fine and cold! Maybe a slow leak?

Anyhow, went for a drive, exactly the same! But when I came home, realised the compressor was idling, not locked-up, and after system swithed off for a while, when turned on, a few seconds later the compressor would kick-in and there was the cold air! (The warm air was obviously just the ventilation system without a/c and the 'smell' was the 'outside world'!!!)

By the way, the AC and REC lights havent flashed indicating a fault!!

So what controls compressors??

Thanks,

Kevin