Help Needed With Air Con

[biddy]

Ok after having no A/C in my car since I bought It I decided to try and sought it out. I discovered that the compressor was disconnected so re-connected to no avail. I eventually got it to work by manually pressing the relay together and so managed to check that the compressor was working. Went for a drive and its as cold as ice so I know the gas is ok. Once I remove the cable tie off the relay the compressor dis-engages.

Whilst the relay is over ridden everything seems to work ok, I can change from hot to cold, move direction but just can't get the compressor to work automatically.

I've been through the diagnostic mode with no faults. I've checked all the connections behind the relay and I've got power to both the coil and switch. I'm assuming that means its the negative thats switched not the positive and I think thats were the fault is.

Has anyone had this problem? The only thing I can think it is is the a/c controls in the dash but it seems strange how its doing all the other things its supposed to except switch the compressor on.

[noone]

Sounds very similar to what my 32gtr was doing, then I blew the motor

Am now back on the road and got the system regassed this morning

and both fill point lines froze up almost immediatly got about half a charge in there they reckon

DAMN

will let u know how I go over the next coupla days mine used to be like yours almost to the letter

could bridge the relay and worked well but wouldnt pull the clutch in any other way

guy who filled it mumbled something bout the tx valve but openly admitted he just tops em up an isnt a fridgy

will be seeing another supposed expert Monday

[biddy]

Yeah, I've even tried to disconnect the pressure switch and bridge that but that does nothing also. I've tested the pressure switch for continuity which seems ok so i'm assuming there is enough gas in there.

[noone]

Spoke to an aircon guy yesterday who reckons alot of people mistakingly over pressure these systems

doubt that would stop the comp kicking in though

Just lotsa drag once its running

[Dose Pipe Sutututu]

Usually those switches are 2 ways, either over pressure or no pressure, best bet is to go to an local mechanic and use their A/C gas gauges and see if there's 1. enough gas 2. not enough gas 3. system is vacuumed properly

[noone]

wont be vacuumed if is full will it?????

And does anyone actually know the correct pressure amount for a charge in these systems??

[biddy]

Ok, I got a couple of wiring diagrams off another member and i've checked continuity between all connections between climate control unit, ecu and relay. I've got continuity between them all. The only fault I could find was the voltage at the ecu which should be battery voltage when the a/c is off and 0 volts when it is on. So it looks like its the ecu. I've also got the same problem with the thermo fan. If I bridge the teperature switch and then earth the connection which goes back to the ecu the fan works. Looks like the ecu isn't switching the relays to earth as it should be.

Does anyone know if these settings could of been changed when I had a nistune fitted?

Cheers Paul.

[noone]

The only fault I could find was the voltage at the ecu which should be battery voltage when the a/c is off and 0 volts when it is on. So it looks like its the ecu.

Mine Has now been regassed correctly and by bridging the switch at the relay pins 3 & 5 the clutch kicks in otherwise it wont, DAMN.

pin 9 at the ECU has 12v with ignition on drops to 11v if ya turn the A/C on assume thats the one you r referring to above???

The manual says to earth pin 46 an it should bring in the clutch if it doesnt its the ecu

Also noticed today the overheat fan isnt kicking in either, previously (before I owned the car) the A/C guys bridged the earth and power pins at the relay to bring the fan on with the A/C cant see how that would stop it working now though.

Am considering a manual switch at the dash to pull the clutch in and another for the overheat fan Dodgy I know but it would work

Mine is a Powerfc not a nissan ecu but appears to be the same problem ecu isnt pulling the clutch relay (and I suspect the overheat fan relay) down to earth to power them on just curious, is your ecu mounted to the chassis or loose behind the kick panel??????

Dont know if that would help Might give it a go in the morning.

[noone]

Returned wiring on my overheat fan to stock they had completely removed the original earth and had the relay earth for the ac looped to both, fan now comes on at 90 degrees on the PFC so happy there

Still cant get the PFC to earth the AC relay though

Probly burnt out the transistor trying to pull both relays down at once,

NOT HAPPY

[biddy]

Yeah, I've put a switch in to pull the compressor in too. I've also earthed the pin on the temp switch for fan but I still havn't heard it kick in yet. The fan works if I bridge the connections and earth it so it can now only be a faulty temp switch.

[hcR324door]

finely i have found people with the same problem! im also thinking of putting a switch to earth pressure switch. i have also out that the fan on the condenser is not suppose to come on with ac only come at 92d for engine temp,mine has a stock ecu

[noone]

alot of aircon places will assume the fan comes on with the A/C an wire it as such, they are wrong an generally dont like to hear it!!!

Yeah am assuming at this point my only option is to use a switch to earth, however I believe the A/c is sposed to turn off ie. release the clutch at a certain rev's I may be wrong here I know the A/C can change the angle of the clutch plate engagement to reduce load, the manual tells you as much, but can anyone confirm that it will actually drop the clutch out completely????

Plan at this point is to chat to the local distributor of the A/C compressor an see if they can let me know what rev's the compressor is rated to, I can then switch it at this point if required.

[hcR324door]

my mates 32 his clutch engages and stays on all the time does not drop in and out is this right or wrong?please need help,have had many auto elecs look and dont know and in the end told me what i already know for $95 @hr

[4drlvr]

Hi Fellas, I having a similar issue with my 33. The problem is i cant find the damn connector that connects to the compressor from the wiring loom. Can anyone tell me where to find one or what i need to do to create some sort of a switch so that the compressor clutch kicks in?? please

Sorry if its a bit off topic