air con problems in td42 gq patrol

Post by **rumpig89** » Sat Oct 17, 2009 3:48 pm

gday havent been able to find any answers yet.

my air con hasnt worked in a 8-10 months - dont remember it stopping just noticed one day it wasnt cooling at all.

The magnetic clutch on the compressor doesnt lock up, no light on switch... where do i start? Fuse in main box is OK... i assume there must be another somewhere... the fan on front of condenser is really squeeky when i turn it by hand... but still runs when i put power directly on it.

have all grill etc off at the moment so thought i would get it workin...

cheers
matt

Post by **ledgend80** » Sat Oct 17, 2009 4:27 pm

does your blower fan still work
does it have gas in it
if there is no gas in it then your magnetic clutch wont engage
do you have power at your low pressure switch
do you have power at your a/c switch
start with that

Post by **rumpig89** » Sat Oct 17, 2009 5:19 pm

ledgend80 wrote:does your blower fan still work
does it have gas in it
if there is no gas in it then your magnetic clutch wont engage
do you have power at your low pressure switch
do you have power at your a/c switch
start with that

fan works
cant be sure on gas... will check everythin i can before i take it somewhere
NO power at pressure switch... i take it its the one on the little cylinder driverside of radiator (red wire yellow stripe_
Power at a/c switch... but only on one point out of three... even when i switch it (looking through some drawings right now)

Post by **ledgend80** » Sat Oct 17, 2009 6:28 pm

yeah that should be the low pressure switch mounted to your reciever dryer
is one of the 3 wires an earth and if so do you have an earth
does your a/c switch work continuity check
power should go from a/c switch to low pressure switch to a/c clutch could be abit different though

Post by **rumpig89** » Sat Oct 17, 2009 6:31 pm

i have been testing the switch and there are 3 wires going to it - blue, blue-white stripe, yellow.

blue has power to it

no continuity between and of them. I assume the switch would switch between blue and blue-white stripe... no real idea what the yellow is for? (doesnt have an indicator light in switch)

Post by **ledgend80** » Sat Oct 17, 2009 6:42 pm

do any of the 3 wires have continuity to ground or does the switch buy itself have continuity when you press it

Post by **rumpig89** » Sat Oct 17, 2009 8:57 pm

the only continuity to ground is at the blue wire (~40 ohms) - which is positive when turned on - must be measuring through a relay down the system somewhere.

the switch must be dodgy as i cant get any continuity between any of the wires when i press it... i would like to hot wire it to prove to myself that is the prob before replacing. havent had any luck bypassing it so far.

i have been doing this all with the car in the on position - no running... is that ok? i should hear the clutch click and the fan start...

Post by **ledgend80** » Sat Oct 17, 2009 9:33 pm

think you will need the car running. you could just supply 12 volts to the a/c clutch and see if that latches in. but havent had anything to do with a nissan before so not sure how there wiring is done.can you trace where the wires run to. if it was me would just hot wire it. but if you can trace where the wires go to would be good or do your drawings tell you anything

Post by **rumpig89** » Sat Oct 17, 2009 10:20 pm

i hot wired the compressor clutch and the fan earlier... without the car running (jumper at the relay)

so if i had them both going and the car running it should be cooling? ill give that a go then work out whats holding the control circuit from working.

Post by **ledgend80** » Sat Oct 17, 2009 10:28 pm

should if it has gas in it. when you had your jumper in the relay did you have power at the low pressure switch as well. make sure your condensor fan is working or else your condensor will get red hot

Post by **rumpig89** » Sat Oct 17, 2009 11:12 pm

righto i put the jumper in the clutch relay (one in power, one in coil), pulled the clutch in... put the relay in for fan it clicked and fan running.

now have power to pressure switch... pressure switch is open... therefore low gas??

add.. just put both relays back in. at switch using test lamp between earth and either of other two that didnt have power - light dimly glows and clutch and fan start up... maybe an earthin problem somewhere??

am confused as to why the switch doesnt have any continuity between any combination of contacts... has to be faulty

Post by **ledgend80** » Sun Oct 18, 2009 7:28 am

sounds like there could be an earth problem. with the low pressure switch and you say open. is that open as power going through or open as no power going through. did you try it with the car running tosee if you got cold air.

Post by **marin** » Sun Oct 18, 2009 7:33 am

Low gas.

Take it to an fridgy and get your system checked over for leaks, and then regassed.

Post by **rumpig89** » Sun Oct 18, 2009 10:25 am

ledgend80 wrote:sounds like there could be an earth problem. with the low pressure switch and you say open. is that open as power going through or open as no power going through. did you try it with the car running tosee if you got cold air.

no cold air when running.

open as in open circuit - no current flowing through (switched off)

Post by **rumpig89** » Sun Oct 18, 2009 10:29 am

marin wrote:Low gas.

Take it to an fridgy and get your system checked over for leaks, and then regassed.

ok. so that pressure switch should be 'closed' when there is sufficient gas pressure to run system?

Post by **ledgend80** » Sun Oct 18, 2009 12:08 pm

i think you are going to have to take it to an auto elec or a/c shop to get the a/c done. they will check for any leaks and repair you can see if your shrader valve in the test points are tight but you are going to have to take it to an a/c professional. to get it fixed and running 100%. take it to them and see how much to fix. at minimum it will be a regas and 1 reciever dryer to start with plus finding the leak if there is one and any electrical problem that there might be. have fun hope it isnt going to cost to much. dont no how hard the evapourator is to get to or out from under the dash. if they end up pulling it out make sure they clean the fins. just see what a shop says.

Post by **rumpig89** » Sun Oct 18, 2009 12:31 pm

cheers

yeh i have been tracing it out and doin up a drawing... have tracked it down to a thermostat looking thing on the top of the evaporator? (plastic box behind the glovebox)

thanks for your help everyone... get it checked out and gassed up next week.

Post by **rumpig89** » Sun Oct 18, 2009 8:56 pm

all sorted. found the drawing of my system... after tracing most of it out anyhow. Fixed two earths... one for relay coil and one for fan. found out that blower in cab has to be running to have air con - everything clicks in now (with the low pressure switch shorted out)

hopefully just a matter of maybe finding a leak and gassing it up

cheers again for your help legend and marin.

Post by **ledgend80** » Sun Oct 18, 2009 9:01 pm

now you hope it just a loose hose or something for the leak and not the cmpressor or the evapourator or it might get a bit $$$$$

Post by **rumpig89** » Sun Oct 18, 2009 11:22 pm

ledgend80 wrote:now you hope it just a loose hose or something for the leak and not the cmpressor or the evapourator or it might get a bit $$$$$

correct... here's hoping

Post by **rumpig89** » Mon Oct 19, 2009 11:31 pm

gassed up - no leaks anywhere serious... a cap was loose somewhere,

works a charm. bring on summer.

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air con problems in td42 gq patrol

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