Trouble Shooting A/c In R33

[zoomzoom]

Thanks, I have a suspicion that the problem is in that plug. The day when the air con worked, I fiddled with that plug. Maybe the connection isn't very good.

There is pressure in the system, I just don't know how much. I did test the schrader valve on the air con pipes for an instant. If it was genuinely tripping a low pressure switch, it shouldn't be intermittent?

[89CAL]

Shouldnt really. Once its low, its low. without turning the compressor on it cant gain any pressure. Sounds like you might be onto it.

[benl1981]

Just got a couple of questions about the r33 rb25 pins if someone could help, might save raising a new thread as it's still related:

1. does pin46 supply a ground when air con is on and Could I use that to trigger the aircon clutch in place of pin 9? I found pin 46 and it seemed to give about 11.8v when air con off and 0.3v when on but it was hard to get a good connection at the back of the ecu.

2. Also, what triggers the AC condensor fan? Is it engaged when the clutch is engaged? Ie always on if aircon compressor is running

[zoomzoom]

Pin 46 should be the signal from the climate control/ AC control to tell the ECU when the climate control "thinks" the AC should be running. The ECU can disable the AC, for example on wide open throttle, among other situations. It also bumps up the idle to account for the load on the engine. If the ECU allows the compressor to run, then it grounds pin 9.

I would do a lot of research before bypassing factory safety features. For one, does an AC compressor have a rev limit? Does the ECU cut the compressor after a certain RPM?

[zoomzoom]

Ok after a bit of testing on the dryer unit, Im only more confused.

This is all I could determine:

Pink wire - 12v, when earthed it activates the A/C thermo fan

Yellow/black wire - 12v, when earthed it activates the FICD relay

Black - earth? When you bridge the above to this pin they activate

Blue wire - ???. Hard to get a voltage reading. 1v max. Earthing doesnt seem to do anything.

[89CAL]

Where are all these wires (e.g. on the pressure switch) if you can tell me where they are ill see if it all makes sense

[zoomzoom]

Ok, despite my inability to read japanese symbols, I think I have found the correct wiring diagram for a 96 Stagea RS4V, and it clears up a lot of problems.

Turns out a 7.5 amp fuse in the drivers side knee fusebox supplies the AC relay coil, AAC, boost solenoid, VVT and o2 sensor signal. It didn't look blown, but it was and has happened more than once. Since I don't use the boost solenoid, I will disconnect it to reduce the power draw and see if it causes an error. Perhaps a resistor will be needed in to bridge the plug so the ECU still thinks its connected.

[benl1981]

Thought I would report that pin46 does also supply a ground when AC is on.

Got my air con working great by taking a wire across from the pink wire (at the ficd relay) to the pressure switch on the dryer.

I cut the red and green feed to the pressure switch from pin 9 and used the feed from pin 46 instead of the signal from the ECU.

The system cycles the air con perfectly now as the signal is coming from the thermo amp.

You just miss out on the ecu control for disabling aircon on high rpm or high load and also if engine gets too hot. I just turn the AC off if I'm going to lean on it a bit.

My pin 9 wasn't outputting the ground. Could investigate that further later but having working air con is such a luxury..

Good luck zoom zoom

[admS15]

Bumping this thread as I have recently had the dreaded intermittent ac issue which of course started happening on a 40 deg. day and I would like to share my findings. The ac used to work fine, then 1 day decided it had enough of life and the compressor wouldn't kick in although idle up was still working. 2 days later it started working again, lasted a week and then quit for good.

I took the car to an ac place to check it out, was a little low on gas so got it recharged, it started working but was intermittent, ac guy suspected pressure switch so I went and got one from an a32 maxima and fitted it and refilled the gas again. Ac worked ok for about a month, had a few intermittent episodes but ok mostly.

The other day the ac quit again and this time wouldn't come back to life. would work fine if bridged at relay or pressure switch, got my multimeter out and started testing, seemed to be no signal to the pressure switch to activate the compressor. As previously mentioned in this thread, I started looking at the thermistor as this cuts the compressor in and out. I decided to plug in a spare one I had from an s15 I had stripped.

I was a bit hesitant as I thought I would have to pull the dash out. As it turns out it is accessible by just removing the glove box lid and backing plate. Within 10 minutes I was able to unplug the thermistor and then plug in the spare I had from the s15 (plug was different so I just wired it in). Ac started working again. In my case I believe it was just a bad connection at the plug because when I plugged the original back in, everything was fine.

Had I needed to replace the thermistor I would have left the original where it was and just put the new one in a different spot on the core. You can get access to the core by removing the 2 screws that hold the ac power module thingy in and remove it. Through that hole you can reach in with your fingers and push the thermistor into the core, I would then drill a small hole through the plastic casing to feed the plug through and then use some silicon to seal it back up.

So for anyone else that has this issue with their ac compressor not kicking in and everything else checks out ok, give this a go. Doesn't take long at all to plug in another thermistor and test. You could probably get one out of just about any Nissan of the era (e.g a32/33 maxima, s14/15)that uses a similar climate control system for testing purposes b4 u go ordering brand new parts. Having working icy cold ac again is bloody brilliant

[Hazz]

On 01/11/2012 at 2:23 PM, jjman said:

iv had the trouble in my R33 of my ac switching on and the often (but not always) off again after only 5-10 secs of being on (this is in A/C on mode with 18 degrees selected so technically should run indefinately in warm weather as the interior isnt 18degrees before it switches off sometimes). Sometimes it doesnt even switch on.

THo there is no constant situation (like hot or cold ambient) where it runs, is intermittent or doesnt switch on in.

There is plenty of refridgerant as the view glass is nice n green when on and the air is nice and cold.

Iv run the diagnostic mode and no faults.

anybody know what might be the cause of this or experienced it?

otherwise can you access all of the cars sensors via a consult cable and program? im sure that one of the sensors must be shitty and so going outside its operating range quickly and then switching the AC off. Tho its problem doesnt show in diagnostic mode...

Anybody? (i cant go another summer without it working)

Hey buddy, have the same problem with my r33 gtr. Air con just doesnt always work and when it does it can cut out. Noticed that when giving the car a little it cuts out too. Has anyone got a solution to this problem?

[jSbr0]

Thought id post here as ive got problems with a/c in my 33 ? Firstly i thought it was tune related but must have just been the timing of it. Ive had everything checked by a autoelec including the gas (full) Basically i can get it work by earthing pin 9 or 46 Also at the relays and the dryer. Ive even checked continuity again and fuses and tested relays. I also tried a spare climate control box i had and another thermistor with no luck. When i check pin 9 and 46 with the a/c on or off they both show 12v So i take it the ecu is not doing its job and grounding? Anyone know the best way to bypass the ecu? I tried a method posted here but it just pops the a/c fuse.

[SkudR33]

If you twist 9 and 46 it should bypass the ECU and it still retains the use of the A/C button on your console.... ive done the same thing to my car!

[jSbr0]

I gave this a shot with no luck. Still shows a 12v when on or off. Cheers

[bistratoaie]

My clutch slips/plays up when I turn my aircon on, the revs drop a little but my actual clutch doesn't engage or disengage properly and it's really pissing me off! I hardly ever use aircon but with summer here and the Perth heat, I might need it for them extra hot days! Anyone know what's causing this or how to fix it? I know it's not my clutch, I just installed an Exedy HD clutch about 2 weeks ago, cheers

[Mick]

there maybe a relay somewhere that has gone, dod you check out the wiring diagram for the ac to check

[bistratoaie]

@Mick so you think a relay could be gone? which one are you supposing? I have not checked the wiring myself as I'm not the best at electrical problems but if I can narrow it down to exactly what it is then I'll get my older bro to have a look seeing as he's an auto sparky

[Mick]

i will see if i can find out for you, but it makes sense, you can manually power it by delivering 12v to it so my guess would be there is a relay somewhere that is stuck or dead and its not switching the 12v to the aircon. There are many relays in the r33, its just trying to narrow down which one it might be

[Mick]

yes there is indeed a relay, but not sure where in the car it is located

[Mick]

oh isnt it in the black box in the engine bay, have you tested that aircon relay in that box yet?

[89CAL]

Front Fuse Box in engine bay

You can find it in the same wiring manual that the above comes out of. The 'R-9' in the blue box between the relay and harness indicates the item number, then find it in the component locator