Got a strange problem here,went to put on the aircon today and nothing,
Checked fuses even had the gas checked and all fine,
Put a permanant live to the aircon- pump and the clutch engaged so assume 
pump is ok,just strange how it's just died as it worked fine yesterday.
Switch lights up green but nothing engages when fan speed switch is put on,
Any ideas.
Rover 620petrol.

Thanks

"simondo"  wrote in message 
news:JflRe.15984$x4.15431@newsfe3-gui.ntli.net...

> Got a strange problem here,went to put on the aircon today and nothing,
> Checked fuses even had the gas checked and all fine,
> Put a permanant live to the aircon- pump and the clutch engaged so assume 
> pump is ok,just strange how it's just died as it worked fine yesterday.
> Switch lights up green but nothing engages when fan speed switch is put 
> on,
> Any ideas.
> Rover 620petrol.
>
> Thanks
>

How do you know the gas is fine? If the pressure is too low the compressor 
won't engage.

The evaporator thermostat may have failed - it monitors the evaporator 
temperature (inside the car heater box usually) and if it gets *too cold* 
switches off the compressor to allow it to warm up to prevent it icing up. 
It may have failed in a "too cold" state or have an electrical problem.
Follow the wiring back from the compressor and check every relay and switch 
to confirm they are working OK.

Alan.

"Alan"  wrote in message 
news:mAARe.2690$x4.463@newsfe4-gui.ntli.net...

>
> "simondo"  wrote in message 
> news:JflRe.15984$x4.15431@newsfe3-gui.ntli.net...
>> Got a strange problem here,went to put on the aircon today and nothing,
>> Checked fuses even had the gas checked and all fine,
>> Put a permanant live to the aircon- pump and the clutch engaged so assume 
>> pump is ok,just strange how it's just died as it worked fine yesterday.
>> Switch lights up green but nothing engages when fan speed switch is put 
>> on,
>> Any ideas.
>> Rover 620petrol.
>>
>> Thanks
>>
> How do you know the gas is fine? If the pressure is too low the compressor 
> won't engage.
>
> The evaporator thermostat may have failed - it monitors the evaporator 
> temperature (inside the car heater box usually) and if it gets *too cold* 
> switches off the compressor to allow it to warm up to prevent it icing up. 
> It may have failed in a "too cold" state or have an electrical problem.
> Follow the wiring back from the compressor and check every relay and 
> switch to confirm they are working OK.
>
> Alan.
>Will check the switch and the wiring,regarding the gas i know it's spot on 
>as my uncle has a garage and had it back on the machine as it says full 
>with no leaks. 

"simondo"  wrote in message
news:6KFRe.2099$h54.1310@newsfe6-gui.ntli.net...

>
> "Alan"  wrote in message
> news:mAARe.2690$x4.463@newsfe4-gui.ntli.net...
> >
> > "simondo"  wrote in message
> > news:JflRe.15984$x4.15431@newsfe3-gui.ntli.net...
> >> Got a strange problem here,went to put on the aircon today and nothing,
> >> Checked fuses even had the gas checked and all fine,
> >> Put a permanant live to the aircon- pump and the clutch engaged so
assume
> >> pump is ok,just strange how it's just died as it worked fine yesterday.
> >> Switch lights up green but nothing engages when fan speed switch is put
> >> on,
> >> Any ideas.
> >> Rover 620petrol.
> >>
> >> Thanks
> >>
> > How do you know the gas is fine? If the pressure is too low the
compressor
> > won't engage.
> >
> > The evaporator thermostat may have failed - it monitors the evaporator
> > temperature (inside the car heater box usually) and if it gets *too
cold*
> > switches off the compressor to allow it to warm up to prevent it icing
up.
> > It may have failed in a "too cold" state or have an electrical problem.
> > Follow the wiring back from the compressor and check every relay and
> > switch to confirm they are working OK.
> >
> > Alan.
> >Will check the switch and the wiring,regarding the gas i know it's spot
on
> >as my uncle has a garage and had it back on the machine as it says full
> >with no leaks.


An a/c charging machine is not capable of telling you its "full and no
leaks'!!

Either you vac out and weigh what you have an compare to the sticker on the
car, OR you measure high and low pressure ports with the gauges and look on
a chart (which factors in ambient temp). The latter is only any good on an
at least partly working system.

Tim..

> An a/c charging machine is not capable of telling you its "full and no
> leaks'!!


Correct.



> Either you vac out and weigh what you have an compare to the sticker on 
> the
> car, OR you measure high and low pressure ports with the gauges and look 
> on
> a chart (which factors in ambient temp). The latter is only any good on an
> at least partly working system.


Yup. A system with only one tenth of the correct gas charge will still show 
about the right static pressure on a guage.
Only this week I worked on a Passat with this problem. After a Vac and 
charge with the correct quantity of gas it is now working fine again.

"Alan"  wrote in message
news:CaXRe.4322$k4.1417@newsfe4-win.ntli.net...

> > An a/c charging machine is not capable of telling you its "full and no
> > leaks'!!
>
> Correct.
>
>
> > Either you vac out and weigh what you have an compare to the sticker on
> > the
> > car, OR you measure high and low pressure ports with the gauges and look
> > on
> > a chart (which factors in ambient temp). The latter is only any good on
an
> > at least partly working system.
>
> Yup. A system with only one tenth of the correct gas charge will still
show
> about the right static pressure on a guage.
> Only this week I worked on a Passat with this problem. After a Vac and
> charge with the correct quantity of gas it is now working fine again.



Alan, out of curiosity, how long do you tend to vac an average system for?
My instructions say about 15mins, but I hear upwards of 40mins is better
practice (with a standard type vac pump)

Tim..

"Tim.."  wrote in message 
news:dfcmko$peo$1@nwrdmz01.dmz.ncs.ea.ibs-infra.bt.com...

>
> "Alan"  wrote in message
> news:CaXRe.4322$k4.1417@newsfe4-win.ntli.net...
>> > An a/c charging machine is not capable of telling you its "full and no
>> > leaks'!!
>>
>> Correct.
>>
>>
>> > Either you vac out and weigh what you have an compare to the sticker on
>> > the
>> > car, OR you measure high and low pressure ports with the gauges and 
>> > look
>> > on
>> > a chart (which factors in ambient temp). The latter is only any good on
> an
>> > at least partly working system.
>>
>> Yup. A system with only one tenth of the correct gas charge will still
> show
>> about the right static pressure on a guage.
>> Only this week I worked on a Passat with this problem. After a Vac and
>> charge with the correct quantity of gas it is now working fine again.
>
>
> Alan, out of curiosity, how long do you tend to vac an average system for?
> My instructions say about 15mins, but I hear upwards of 40mins is better
> practice (with a standard type vac pump)
>
> Tim..
>
>


Tim, usually about 15 minutes, but my guages sit at the same place and don't 
move any further after a couple of minutes so I'm not convinced the extra 
time does anything worthwhile!

Alan.

Alan wrote:


>>Alan, out of curiosity, how long do you tend to vac an average system for?
>>My instructions say about 15mins, but I hear upwards of 40mins is better
>>practice (with a standard type vac pump)

> Tim, usually about 15 minutes, but my guages sit at the same place and don't 
> move any further after a couple of minutes so I'm not convinced the extra 
> time does anything worthwhile!


The last place I went to left it for an hour. There guages didn't do 
much after 15 minutes either.

John