Hi
Just turned on the Fans and air is coming through, but no cold air. I then opened the bonnet and found out that the compressor wast turning. I Checked the fuses?? (is there one near the Brake fluid res?) inside under the steering wheel fuse and all seem ok. I also unplugged the connector off the compressor body and checked for volts but no volts. Could anyone help me with any ideas?
Many thanks
Jaydev
Compressor not turning
Moderators:davidr, BigCatXJS, dhdove
Compressor not turning
Is the relay (RF3, next to the start relay) receiving power on its 87 pin?
If not, follow the brown/slate wire back back to the line fuse and check this by replacement. Is it putting power out on the 30 pin (green/white wire) ?
If it is getting power, is the relay getting the signal to turn on? Care needed here, analogue meters (or test lights) can fatally damage the microprocessor controller.
If not, follow the brown/slate wire back back to the line fuse and check this by replacement. Is it putting power out on the 30 pin (green/white wire) ?
If it is getting power, is the relay getting the signal to turn on? Care needed here, analogue meters (or test lights) can fatally damage the microprocessor controller.
Al McL
'93 XJS 4.0 - '20 XF 2.0 Sportbrake
'93 XJS 4.0 - '20 XF 2.0 Sportbrake
Compressor not turning
Are you sure there is gas in it?
If there is no gas the pressure switch won't close to bring in the compressor clutch.
I am sorry but I dont know where the low pressure switch is on a V12 but tracing the lines is not difficult. This switch is what makes the compressor run on demand normally.
If it stopped working suddenly and has been run regulary, I would look at the switching circuit itself, but if it hasn't been used in a while, you are probably best taking it to someone who can re-gas it and check the system.
If there is no gas the pressure switch won't close to bring in the compressor clutch.
I am sorry but I dont know where the low pressure switch is on a V12 but tracing the lines is not difficult. This switch is what makes the compressor run on demand normally.
If it stopped working suddenly and has been run regulary, I would look at the switching circuit itself, but if it hasn't been used in a while, you are probably best taking it to someone who can re-gas it and check the system.
'93 4.0 Auto Coupe Flamenco Red.
Compressor not turning
Thanks Guys,
I had it gassed and the Aircon serviced not too long ago and at that time the compressor was turning and switching in and out. Sorry for my ignorance, but where abouts is the F3 Relay?
One other Idea i had was to put 12V on the Compressor pins taking out the wires going to it to eliminate the compressor being duff.
Once again many thanks.
Jay
I had it gassed and the Aircon serviced not too long ago and at that time the compressor was turning and switching in and out. Sorry for my ignorance, but where abouts is the F3 Relay?
One other Idea i had was to put 12V on the Compressor pins taking out the wires going to it to eliminate the compressor being duff.
Once again many thanks.
Jay
Compressor not turning
An Update Guys.
Ok, I found the Relay; I didn’t even know there were Relays under that cover! Anyway there are two F3 relays. I traced the one applicable to the Compressor. I tested all the pins and all was as it should be. I then carried out a continuity test from the relay o/p to the compressor plug, all was ok there. I then powered up the car and put the fans on. With the Multiplug disconnected from the Compressor i checked if i was getting 12V and all was ok there. So, The Electrical side of things ok and it looks as if the right signals are getting from the ECU to the Relay and 12V on the Comp input.
So traced back the other wire (presumably the earth) to the back of the compressor, voila! This is the pressure switch that earths the compressor and makes the circuit.
So, with the engine running and the Fans on i temporarily set up an earth bypass to the compressor. It now Turns! It only needed a kick start and i disconnected the bypass and the magnetic clutch was still engaged.
The sad story is that i had the system gassed and on the cold send pipe from the compressor the pipe was not cold as it was before. So the gas has escaped
This leads me to believe that the electrical system including the pressure switch, are all ok and functioning correctly.
When i had it gassed, the chap put in 134a and i think it had R12 in it. Incompatible perhaps?
Anyway, I will give him a call this week and ask him to investigate.
Many thanks for all your help on this gents.
Cheers
J
Ok, I found the Relay; I didn’t even know there were Relays under that cover! Anyway there are two F3 relays. I traced the one applicable to the Compressor. I tested all the pins and all was as it should be. I then carried out a continuity test from the relay o/p to the compressor plug, all was ok there. I then powered up the car and put the fans on. With the Multiplug disconnected from the Compressor i checked if i was getting 12V and all was ok there. So, The Electrical side of things ok and it looks as if the right signals are getting from the ECU to the Relay and 12V on the Comp input.
So traced back the other wire (presumably the earth) to the back of the compressor, voila! This is the pressure switch that earths the compressor and makes the circuit.
So, with the engine running and the Fans on i temporarily set up an earth bypass to the compressor. It now Turns! It only needed a kick start and i disconnected the bypass and the magnetic clutch was still engaged.
The sad story is that i had the system gassed and on the cold send pipe from the compressor the pipe was not cold as it was before. So the gas has escaped
This leads me to believe that the electrical system including the pressure switch, are all ok and functioning correctly.
When i had it gassed, the chap put in 134a and i think it had R12 in it. Incompatible perhaps?
Anyway, I will give him a call this week and ask him to investigate.
Many thanks for all your help on this gents.
Cheers
J
Compressor not turning
Jay
It's a sad fact that not everyone working in the air con business is scrupulous. If you ask for a regas, some will happily do it even when they know there's a leak. They shouldn't, but hey, it makes them money.
What should now happen is that the leak should be found and fixed and the system ought to be evacuated and its ability to hold a vacuum demonstrated. (If they tell you it's a leak in the evaporator ask for positive evidence or find another place.) Then the specified refrigerant charge should be added.
If your system was converted to R134A from R12, the charging points should have been changed from the capped schrader valves to the quick release style (red and blue) fittings. A notice should also have been stuck on stating the change and the charge weight. If this wasn't done suspect the quality of the job.
The problem with a 'top-up' (as advertised by a well known high street chain of fraudsters) is (as you have discovered) it leaks away again, and no one has any idea how much of the original charge is left and as a result no idea how much to add. To get round this some air con techs will measure high side pressure. Unless they have a pretty heavy duty cooling fan in use, this almost always leads to under charging and inefficient cooling as a result.
It's a sad fact that not everyone working in the air con business is scrupulous. If you ask for a regas, some will happily do it even when they know there's a leak. They shouldn't, but hey, it makes them money.
What should now happen is that the leak should be found and fixed and the system ought to be evacuated and its ability to hold a vacuum demonstrated. (If they tell you it's a leak in the evaporator ask for positive evidence or find another place.) Then the specified refrigerant charge should be added.
If your system was converted to R134A from R12, the charging points should have been changed from the capped schrader valves to the quick release style (red and blue) fittings. A notice should also have been stuck on stating the change and the charge weight. If this wasn't done suspect the quality of the job.
The problem with a 'top-up' (as advertised by a well known high street chain of fraudsters) is (as you have discovered) it leaks away again, and no one has any idea how much of the original charge is left and as a result no idea how much to add. To get round this some air con techs will measure high side pressure. Unless they have a pretty heavy duty cooling fan in use, this almost always leads to under charging and inefficient cooling as a result.
Al McL
'93 XJS 4.0 - '20 XF 2.0 Sportbrake
'93 XJS 4.0 - '20 XF 2.0 Sportbrake
Compressor not turning
Any decent Fridge engineer will do all the items below when gassing a system:
1. Recover all Gas from the system (if any left!)
2. Pressure test the system (normally with dry spot Nitrogen) - to check the integrity of the system. It is illegal to gas up the system until successful pressure test has been conducted (all leaks have been fixed). It is not always the case that the system has any leaks and if the system has not been run over winter the gas can leak out of a perfectly good compressor seal (always good to run your system at least once a week
)
3. Dehydrate system with a vacuum- this needs to be done to get rid of any moisture in the system. Then conduct a vacuum drop test to make sure all moisture has gone (and it gives a second integrity test).
4. Re-charge with Fridge Gas (breaking the vacuum with the fridge gas so no Oxygen (hence moisture) gets into the system.
Now I have never used the well known chain that have been mentioned but I cannot believe they do all this for the prices they quote. Also I have seen Halfrauds selling 134A in a tin which means any Tom Dick or Harry can have a go when not understanding the system.
R134a can be used instead of R12 if the compressor oil is changed and is a little less efficient but industry has used this drop in gas for a while. Other Air con engineers use RS12 which uses the same oil as R12.
Hope this helps
1. Recover all Gas from the system (if any left!)
2. Pressure test the system (normally with dry spot Nitrogen) - to check the integrity of the system. It is illegal to gas up the system until successful pressure test has been conducted (all leaks have been fixed). It is not always the case that the system has any leaks and if the system has not been run over winter the gas can leak out of a perfectly good compressor seal (always good to run your system at least once a week
)3. Dehydrate system with a vacuum- this needs to be done to get rid of any moisture in the system. Then conduct a vacuum drop test to make sure all moisture has gone (and it gives a second integrity test).
4. Re-charge with Fridge Gas (breaking the vacuum with the fridge gas so no Oxygen (hence moisture) gets into the system.
Now I have never used the well known chain that have been mentioned but I cannot believe they do all this for the prices they quote. Also I have seen Halfrauds selling 134A in a tin which means any Tom Dick or Harry can have a go when not understanding the system.
R134a can be used instead of R12 if the compressor oil is changed and is a little less efficient but industry has used this drop in gas for a while. Other Air con engineers use RS12 which uses the same oil as R12.
Hope this helps
1986 3.6 MANUAL (WAHOO FINISHED FULL RESTORATION!!!!!!!!!)
1998 MK IV TOYOTA SUPRA TT VVTI
LIVING THE DREAM
1998 MK IV TOYOTA SUPRA TT VVTI
LIVING THE DREAM
Compressor not turning
Thanks for all your comments and help on this chaps.
In the engineers defence he did replace the condenser and did mention that there was an absolute minute leak, very negligeble. and he did say that It could last up to a year and a half. But sadly didnt.
Hopefully i will get it sorted for the Scorcher Summer we are going to have!
I will let you know how I get on.
Cheers
J
In the engineers defence he did replace the condenser and did mention that there was an absolute minute leak, very negligeble. and he did say that It could last up to a year and a half. But sadly didnt.
Hopefully i will get it sorted for the Scorcher Summer we are going to have!
I will let you know how I get on.
Cheers
J
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