Aircon Doesn't Work (go Cold)

[dori34]

can anyone help me on this issue?

the aircon was working fine with the old rb20 motor. is there some wire issue i gotta sort out here?

my mechanic who did the conversion said that the gas was untouched so it should still be in there.

it happened after doing a rb25 (r33 s1 motor) into a r32.

the fan turns on and everything and just blows out hot air or whatever the outside temperature is.

any help would be much appreciated.

[blind_elk]

The ECU is involved in the A/C operation. I don't recall off-hand which 2 wires are involved, and I still don't know how they affect the A/C and make it work (I think they control the compressor). I still have to work it out on my own system.

[BH_SLO32]

The ECU is involved in the A/C operation. I don't recall off-hand which 2 wires are involved, and I still don't know how they affect the A/C and make it work (I think they control the compressor). I still have to work it out on my own system.

You will need to connect Pin 46 (AC switch signal) and pin 9. The ECU earths pin 9 (compressor relay) when the AC button is activated.

Pin 9 wire comes from the engine bay plug near the power steering reservoir. Pin 46 is one of the wires in one of the plugs near the ECU.

[dori34]

BH_SLO32 Posted Today, 01:53 PM

QUOTE(blind_elk @ 17 Dec 2007, 09:33 AM)

The ECU is involved in the A/C operation. I don't recall off-hand which 2 wires are involved, and I still don't know how they affect the A/C and make it work (I think they control the compressor). I still have to work it out on my own system.

You will need to connect Pin 46 (AC switch signal) and pin 9. The ECU earths pin 9 (compressor relay) when the AC button is activated.

Pin 9 wire comes from the engine bay plug near the power steering reservoir. Pin 46 is one of the wires in one of the plugs near the ECU.

sweet!

ill give this a try

thanks BH

[BH_SLO32]

sweet!

ill give this a try

thanks BH

Let me clarify! You need to make sure pin 9 & 46 RB25 wires are connected to the old pin 9 & 46 RB20 wires! Don't join the 2 together. You should have battery voltage at pin 9 & 46 when the AC is off and close to 0V when AC is activated.

Cheers

[blind_elk]

Thanks BH. So how should I make it work? I'm envisioning that I get the old pin46 wire to switch a relay which in turn allows the old pin9 to connect to earth. Sound good?

[dori34]

where do i find wires 9 & 46 on the rb20 ?

any help? which plugs to look after etc.

should it be in the ecu area or behind the aircon?

[blind_elk]

where do i find wires 9 & 46 on the rb20 ?

any help? which plugs to look after etc.

should it be in the ecu area or behind the aircon?

The wires will be at the ECU plug. There will be a pinout and plug diagram somewhere around here.

[dori34]

um i removed my RB20 complete so there will be no ECU plug there

only the rb25 one which i have already found.

i need to bridge them to pin 9 and 46 like bh said on the rb20 side??!!

any more specific detail like what sorta colour the wires are and is there any patterns or markings on them.

Edited December 18, 2007 by whyte

[BH_SLO32]

um i removed my RB20 complete so there will be no ECU plug there

only the rb25 one which i have already found.

i need to bridge them to pin 9 and 46 like bh said on the rb20 side??!!

any more specific detail like what sorta colour the wires are and is there any patterns or markings on them.

I'll give you a detailed rundown tonight if I get time. Whenever I do a loom I always use the factory plugs (that plug into the body loom plugs) on the RB20 loom by simply integrating into the RB25 (or other) loom (RB25 loom with RB20 body loom plugs). This makes the loom a 'plug'n'play' loom.

Pin 9 (AC cut signal - activates the compressor by earthing the compressor relay) is one of the wires that runs to the 8 pin plug near the power steering reservoir. I will give you the colour code tonight if I get a chance. If the mechanic used the RB25 plug (which will plug straight in), it should be connected to the correct wire from memory.

Pin 46 wire in the RB25 loom runs from the ECU to the big plug near the ECU (normally this is connected to the body loom in the passenger foot well). If the mechanic likes attention to detail, he will have removed the factory R33 plug and somehow connected the necessary RB25 wires to the factory R32 body loom plugs. Presumably pin 46 wire is not connected.

If I get time tonight I will give you wire colours.

Cheers

[dori34]

okay cool,

i know whic big plug near the ecu you are talking about.

just need know find out which wire on the big plug to connect appreciate all the help mate.

that was the plug i had to tap into to get my wipers working.

yeah i used a rb25 loom and whatever could be connected was connected.

Edited December 18, 2007 by whyte

[BH_SLO32]

Thanks BH. So how should I make it work? I'm envisioning that I get the old pin46 wire to switch a relay which in turn allows the old pin9 to connect to earth. Sound good?

No, from what I can tell the ECU outputs battery voltage from pin 46 and gets earthed when the AC button is pressed. The ECU then detects this and responds by earthing pin 9 (through the ECU). I recently had trouble with my AC following a malfunction of my Haltech which wasn't earthing pin9 when the AC was activated so I provided a TEMPORARY bypass to a switch which was earthed. This allowed me to manually switch the AC compressor on when I switched the climate control on.

You will simply need to connect pin 46 wire from RB25 loom to the old RB20 wire and likewise for pin 9.

Cheers

[BH_SLO32]

The wire colours are as follows:

RB20DET

Pin 9 is a light green wire sourcing power from the 8 pin plug near the power steering reservoir.

Pin 46 is a Light green wire with a red stripe. It is one of the wires terminating at one of the 3 in-cabin plugs near the ECU. There are 2 white plugs (12 and 16 pins) with small terminals and one 12 pin plug with larger terminals and yellow backing. The wire for pin 46 terminates in the 16 pin white plug (2nd terminal in from the end on bottom row).

RB25DET

Pin 9 is a green wire with red stripe sourcing power from the 8 pin plug near the power steering reservoir.

Pin 46 is a pink wire. It is one of the wires terminating at small end of the main plug near the ECU. It is the very first wire on the top row at the small end.

I will prepare some sketches and attach when I get some time.

Cheers

Edited December 18, 2007 by BH_SLO32

[blind_elk]

No, from what I can tell the ECU outputs battery voltage from pin 46 and gets earthed when the AC button is pressed. The ECU then detects this and responds by earthing pin 9 (through the ECU). I recently had trouble with my AC following a malfunction of my Haltech which wasn't earthing pin9 when the AC was activated so I provided a TEMPORARY bypass to a switch which was earthed. This allowed me to manually switch the AC compressor on when I switched the climate control on.

You will simply need to connect pin 46 wire from RB25 loom to the old RB20 wire and likewise for pin 9.

Cheers

OK, so I set up:

+12V -- relay pin 85 -- relay coil -- relay pin 86 -- wire 46 -- A/C button (-- earth)

A/C wire 9 -- relay pin 30 -- relay switch -- relay pin 87 -- earth

Yes?

(because I'm running a wired-in Wolf 3D that knows nothing about A/c)

[BH_SLO32]

OK, so I set up:

+12V -- relay pin 85 -- relay coil -- relay pin 86 -- wire 46 -- A/C button (-- earth)

A/C wire 9 -- relay pin 30 -- relay switch -- relay pin 87 -- earth

Yes?

(because I'm running a wired-in Wolf 3D that knows nothing about A/c)

You know your relays, very good. In theory this setup should work. Let me know how you go. Since you know your relays, I also install a relay to activate the FICD solenoid on the RB25s because the RB20's don't have one. The FICD is used to increase the idle when the AC is turned on. It is part of the AAC assembly and has a purple 2 pin connector. I use a relay triggered by the 12V feed to the compressor to switch it on. If the wolf was not tuned with the AC on it might be worth considering when you do get the AC going. I can do a sketch of the setup with some photos if you need.

PS. You have no spare auxilary inputs/outputs on the Wolf?

A photo of the R32 in-cabin plug with the pin 46 wires connected (pink wire connected to light green wire with red stripe)

http://www.skylinesaustralia.com/forums/ga...image53334.html

A photo of the RB25 plug near the ECU. Notice the pink wire (pin 46 wire) at the small end of the plug

http://www.skylinesaustralia.com/forums/ga...image53344.html

Edited December 19, 2007 by BH_SLO32

[dori34]

thanks heaps BH! ill have a crack at it soon and let you know how it goes.

hope this works ^^

cheers

[dori34]

okay ive had a go and it still doesnt work.

ive connected both pin 9 and pin 46 on the rb20 loom to the pin 9 and pin 46 on the rb25 plugs.

these are the two plugs near power steering resevoir. theyre both 9pins tho not 8.

refer to pics - the one thats not plugged in and left exposed, do i tap in the light green from that wire and tap into the other connected plug or do i run it to pin 9 on the ECU ? when i tap it from the plug thats connected next to pwer steering resevoir to pin9 on the ecu, i can hear the relays clicking. does this mean its working ? the relay only clicks on when the car is off tho, when i turn it on i dont hear the clicking anymore.

as for pin46.

ive connected the pink last wire (big white plug) to the light green with red stripes (on the little white plug).

ive also tried from the ECU(pin46) to the pink wire on the big white plug and also from ecu to the light green with red stripes on the white little plug.

pin46 on ecu to light green with red stripe on rb20 body loom plug (small white one 12pins)

pink wire on top row (big white plug) to light green with red stripe on rb20 small white plug

is the white 12 pin lil plug on the rb20 loom near the ecu or is it from behind the aircon unit?

any help on what im doing wrong here?

cheers

Edited December 19, 2007 by whyte

[BH_SLO32]

okay ive had a go and it still doesnt work.

ive connected both pin 9 and pin 46 on the rb20 loom to the pin 9 and pin 46 on the rb25 plugs.

these are the two plugs near power steering resevoir. theyre both 9pins tho not 8.

refer to pics - the one thats not plugged in and left exposed, do i tap in the light green from that wire and tap into the other connected plug or do i run it to pin 9 on the ECU ? when i tap it from the plug thats connected next to pwer steering resevoir to pin9 on the ecu, i can hear the relays clicking. does this mean its working ? the relay only clicks on when the car is off tho, when i turn it on i dont hear the clicking anymore.

as for pin46.

ive connected the pink last wire (big white plug) to the light green with red stripes (on the little white plug).

ive also tried from the ECU(pin46) to the pink wire on the big white plug and also from ecu to the light green with red stripes on the white little plug.

pin46 on ecu to light green with red stripe on rb20 body loom plug (small white one 12pins)

pink wire on top row (big white plug) to light green with red stripe on rb20 small white plug

is the white 12 pin lil plug on the rb20 loom near the ecu or is it from behind the aircon unit?

any help on what im doing wrong here?

cheers

I think you have wire up pin 46 correctly although I will have to have a look in my own car at the body loom plugs. The white plugs in my photos are the mating plugs from the RB20 loom to the ones you have photographed.

From what I can tell your mechanic has used the RB25 plug at the power steering end. Unfortunately Nissan swapped the location of the pin 9 wire in this plug so by simply plugging the RB25 plug into the RB20 loom plug you won't get the AC compressor to work. On the RB25 end of the plug shown in your first photograph you need to connect the green wire with red stripe (bottom right when looking into the open plug) with the relevant RB20 body loom wire (see photos). Please note that I have used the RB20 mating plug hence the wire colours will look different to yours.

As a test to see if your compressor is working, connect a probe or piece of wire to the wire as shown in the photos. With the ignition on, if you connect the other end of the wire to ground you should hear the compressor clicking. This wire needs to be connected to the RB25 wire as described above. I will try and make some time tomorrow to take some photos of the plugs near the ECU.

Hope this helps.

Cheers,

Ben

[dori34]

well when i connected pin 9 from engine bay to ecu pin 9.

i could hear the relay clicking when turned off but when ignition is on i cant hear it anymore, i havent tried if it clicks when i turn on the a/c tho.

also what is the left over plug next to the power steering res. any ideas?

man this problem is giving me a headache...

summer is coming too

Edited December 19, 2007 by whyte

[BH_SLO32]

well when i connected pin 9 from engine bay to ecu pin 9.

i could hear the relay clicking when turned off but when ignition is on i cant hear it anymore, i havent tried if it clicks when i turn on the a/c tho.

also what is the left over plug next to the power steering res. any ideas?

man this problem is giving me a headache...

summer is coming too

You shouldn't be able hear a relay clicking when you connect pin 9 unless you have switched the AC on (and assuming pin 46 is wired correctly). Did you try switching the compressor on by probing the wire as shown in the 2nd photo? Earthing this wire will activate the compressor (assuming the clutch is ok).

The other plug I have only ever seen with auto's (or RB26's for fuel injector resistor pack and boost solenoid), so just ignore these wires as they are no longer required (assuming you have a 5 speed now).

If you were local I would offer to fix it for you but given this is not the case I will try and do a step by step guide with photos. I am busy each evening this week with an engine replacement for my sisters car so I have limited time. I am off for a couple of weeks over Christmas so I will attempt to prepare something then if not sooner.

Edited December 19, 2007 by BH_SLO32