HEVAC book symbol question

Hi all,

Wondering if anyone has had this and what was the reason.

When starting up from cold there is no book symbol. A/C is off by the way - after a few minutes when the temp needle has moved up a bit into the blue zone the symbol appears. The various air vent switches do their job and the temp selector raises and lowers the temp of the air both sides.

If the engine is switched off then restarted while still hot then the book symbol does not return.

The little fan under the clock does not run ( it is clean in there though ) and the A/C does not send in cool air ( though compressor engages and one of it's pipes gets hot) - not sure if that info is relevant.

Thanks for any input

I'd guess your aircon refigerant has all escaped, particularly as you are not getting cool air. Age rots the condenser unit.

This is what happened to mine.

notpc said:

I'd guess your aircon refigerant has all escaped, particularly as you are not getting cool air. Age rots the condenser unit.

This is what happened to mine.

Click to expand...

Compressor would not engage and run if there was no refridgerant.

Wammers, you are correct in theory.

Sadly, on mine, the compressor started to work one day with my system empty and quickly started making a very strange noise. Oddly enough, it seized. I still don't know why this happened after the system had been empty for two years, but I still possess the evidence.

On the other hand, I admit you have probably disposed of my suggestion.

I had the same thing a few days ago. The faults indicated two of the blend motors, one open circuit, one short and they wouldn't clear. However the heater was working happily. I cycled through the buttons a few times, no joy. I left it for warmer times before ripping the dash out.

Then today no book!!

I'm going to put it down to sticking flaps and ignore it, unless it comes back in summer, then I might investigate.

Try cycling through the various directions at different temperature, low/high - it might just be sticky flaps/blend motors as was mine, otherwise get air-con checked!

If one pipe from the compressor is hot and the other freezing cold, you have got some gas in thee system and the compressor seems to be working ok. Whether you have the right quantity of gas (Approx. 1250gms) is another matter. Get the pressures and quantity checked for good measure.

I had book symbol come up a while after engine warm up. After fitting new cooling system radiator a year ago, its never come on again.

I think you'll find it's the tempreture sensor fitted to the ally pipe that goes into the heater core. About £15.

notpc said:

Wammers, you are correct in theory.

Sadly, on mine, the compressor started to work one day with my system empty and quickly started making a very strange noise. Oddly enough, it seized. I still don't know why this happened after the system had been empty for two years, but I still possess the evidence.

On the other hand, I admit you have probably disposed of my suggestion.

Click to expand...

Strange things can happen. Normally the system pressure switch makes compressor open circuit without gas pressure in system. So that the compressor cannot run as yours did. There is no Faultmate code for low gas pressure. It just says "Compressor open circuit" which basically means no gas or the switch is duff.