A/C install how to

Website · Post by **frosted flakes** » Sat Jun 12, 2004 7:41 am

Its summer time and I know you guys want a/c.

Some of those hardcore racers would say "a/c is for wimps" but I don’t want my car "full race". I want my car "nice and fast". I want some luxuries in it so that’s why I got a/c.

So here is how I got the a/c to work. (For a 1992 s13)

Step 1) Find the plugs from the skyline wiring harness that goes into the a/c compressor. Cut the lines and plug into the compressor. You will only need the plug with 1 wire going into it (blue wire).

Step 2) Find the original blue/green wire along the harness by the power steering reservoir that went to the KA compressor. Splice this wire to the blue wire onto the RB compressor.

Step 3) Now at this point it’s ready to test if your a.c compressor is not seized up. If it’s seized up then get ready to pull out your compressor and locate another one, or optionally now is the time to remove your entire a/c system.

Now locate the a/c relay in the relay box by the air filter location. Open up the upper relay case for the a/c relay. Now turn on your car.

Now see the contact switch on the relay? Click it and see if it turns the a/c compressor on. If it’s not locked up then it will kick on without any belt squeal and your rpms will go down a little. Only have that a/c compressor on for a SHORT while just to see if it’s locked up. You don’t want to run the a/c compressor very long since its just sucking in air.

If it works go to the next step if not then get another compressor or give up on a/c.

Step 4) This is the hard part. Get custom a/c lines made. We got sent around from shop to shop to see who would get them made....finally after 5 shops we found one that will do custom a/c lines.

I had to use both the KA original a/c lines from the compressor and the RB compressor lines. We got them matted together at a shop for about 50 dollars each. We had to get an r134a Schrader valve fitting brazed on to the low compression side so you are able to fill with Freon.

Also the low compression a/c line gets close to the exhaust side of the turbo so you need to get some high temp wrap to protect the line from melting.

Now is the time to install a new a/c dryer also.

[IMG]http://images.cardomain.com/me...l.jpg[/IMG]

Step 5) Now that you got your a/c lines in and you know that your compressor is good rig up a switch to turn on/off the a/c compressor.

Locate the a/c relay in the relay box by the air filter. Open the box up and find the wires that goes into the a/c relay. Have a multimeter ready and set up for continuity testing. Make sure the blue/orange wire and blue/green wire make continuity when the relay switch is pushed down.

Now that you know it makes continuity you can cut these wires and extend the lines to the driver side and make an a/c on/off switch. I just placed mine below the pop-up headlight switch.

Step 6) Now vacuum system to purge out the moisture. Turn on your engine. Fill with Freon, r134a or r12 with the a/c switch on. Now you got COLD AIR in about 5-10min of running your engine. ENJOY!!!

Post by **93RPS13** » Sat Jun 12, 2004 7:41 am

NICE!!!!

Post by **BoostFab** » Sat Jun 12, 2004 7:41 am

it would be nice if we can extend this further to use the 240's ac controller center console.

Post by **JonPowell** » Sat Jun 12, 2004 7:41 am

Be careful doing this, you are disposing of all the monitoring sensors and safety devices doing this. the pressure switches are there to help shut down the system if pressures get too great. A manual switch stops them from doing their job and can result in a blown compressor.

Website · Post by **frosted flakes** » Sat Jun 12, 2004 7:41 am

that is true...but its kinda hard to do this right...

Post by **gprodigy85** » Sat Jun 12, 2004 7:41 am

most things are... but in the end its worth it

Post by **JonPowell** » Sat Jun 12, 2004 7:41 am

I just want to inform eeryone of the risks before they follow blindly...compressors and condensers aren't cheap.

Post by **NotDave** » Sat Jun 12, 2004 7:41 am

frosted flakes

can u give us an update on how your a/c is running.

Website · Post by **frosted flakes** » Sat Jun 12, 2004 7:41 am

i had a leak in my a/c evaporator (thing in dash)...i just recently got it replaced it and now i have to vacuum my system and see how it works again...but when i freshly recharged the system it was blowing REALLY cold air...

Post by **lyon23** » Sat Jun 12, 2004 7:41 am

i'm working on mine right now and i'm trying to do the wiring throught the rb computer and have all the switches on... I ran it straight like u said and after 2 minutes my line froze. I definately dont want to be turning on and off with a switch... but is very tempting cuz it sure felt good... really really gooood..I'm trying to find a 95 wiring diagram, the closest I got was a 95 altima and I got a couple of diagrams for the 95 240 f3 plug, rb20 ecu pin out and the wulfgang gtr plugs diagram...If i get it working I'll let u guys know.

Post by **FAST-DATSUN** » Sat Jun 12, 2004 7:41 am

On the S13 you can usr the stock ac wiring to run the system as its part of the body and not the engine harness.........

Post by **lyon23** » Sat Jun 12, 2004 7:41 am

I found this on the fhreshalloy forum under 240 advance

"***** this is the big secret that the wiring people wont tell you ****

on the f3 conector (big white plug under dashboard near passenger foot well , you know the one you have to splice into to make your engine swap work) you need to splice together the following cables pin 16 yellow/ black to pin 43 or 46 (cant remeber now im at work) black/pink. and what do you know voila it works, push the a/c button a/c turns on, pust it again it turns off. 2 friggin wires, it was staring me in the face for like a week before i tried it , it seemed to easy, thats it just sauder those two wires togerther and ti will work like stock.

the only issure is wiring it into the idle air control valve so the rpms wont drop as much but i dont really think that is an issure as i have not had any problems with it yet its not to bad but i already pretty much got that figured out and iwill be doing it at some point later this week i will post it then. hope this helps some of you people sweating in your car, cuz ill tell you here in miami i is hot as biatch"

I think I'm going to try it tomorow and see how it does.

Post by **DAEDALUS** » Sat Jun 12, 2004 7:41 am

I don't know which pins are which, but I'm guessing that method only provides on/off control from the controller. The issues that Jon pointed out with the protections being removed are probably still a problem. There is a temp switch and a dual pressure switch that are there to shut the system down when it needs to be. Again, just a guess. Pull the wiring diagram to find out for sure.

Post by **S13Sil-line** » Sat Jun 12, 2004 7:41 am

Hey Lyon. I just searched my a$$ off for 30 minutes trying to find that info. Do you remember exactly what wires or can you send me a link to it?? Pin 16 would be on the F3 connector right? I just checked the pinout diagram and it shows 46 being the signal from the A/C. Correct Right,

Post by **JonPowell** » Sat Jun 12, 2004 7:41 am

Plus it is supposed to shut down the AC at WOT so you can send all the power to the wheels....

Post by **lyon23** » Sat Jun 12, 2004 7:41 am

S13sil here you can do a search for f3 plug and get a 96 pin out and color http://forums.freshalloy.com/u...=5&o=

and I went to rb20det.com here and got the ecu pinout no color though

http://rb20det.com/ecupinout.html

you can read some of wulfgangs info on the a/c and pin out here

http://www.nissaninfiniticlub....43280 and you can see his pdf diagram here(very helpful I might add coudldn't have done mine with out this)

https://netfiles.uiuc.edu/dsta...s.pdf

Post by **lyon23** » Sat Jun 12, 2004 7:41 am

you got a point Jon and that's why I'm trying to run it through the ecu and be safe... like you said in another thread compresor and clutch arent cheap specially not in this case.

Post by **JonPowell** » Sat Jun 12, 2004 7:41 am

I am trying to figure it all out, I just need an install candidate willing to pay for the lines and I will get it worked out...

Post by **S13Sil-line** » Sat Jun 12, 2004 7:41 am

So I connect Pin 16 from the F3 connector to the Pin on the ECU giving the signal from the A/C. Right.

Post by **JonPowell** » Sat Jun 12, 2004 7:41 am

Just run a wire from a toggle switch from the ****pit to the compressor

flip up, onflip down, off

That is the simplest way, not anywhere near safe or reliable, but easy. I dont recommend it at all, but it is by far the easiest way.

Post by **S13Sil-line** » Sat Jun 12, 2004 7:41 am

I would rather have safe and reliable.

Post by **lyon23** » Sat Jun 12, 2004 7:41 am

i'm not sure if my findings are correct but the 95 ka24 a/c setup cannot be made to work with the rb20 computer. the ka a/c has a ac switch, cut off, and 2 wires for the triple presure that talk to the ka ecu and lets it know when to turn on and off. on the rb ecu all you have is the line for ac switch and ac cut off. there is no wire on the rb computer for an a/c thermo or triple presure switch.. i'm not sure how the earlier model 240 a/c setup is but is there a way to get a presure switch or any other part that will turn the compressor on and off and be safe? I'm goin to try and find an rb20 ac diagram and see if it makes more sense.

Post by **S13Sil-line** » Sat Jun 12, 2004 7:41 am

So this is all about an RB20DET. Would it be much different than the RB25DET?

Website · Post by **frosted flakes** » Sat Jun 12, 2004 7:41 am

ive used the on/off switch this summer so far with it working with perfect COLD results...no damage to compressor yet...i love a.c with rb power!

Post by **Wulfgang** » Sat Jun 12, 2004 7:41 am

lyon23 wrote:i'm not sure if my findings are correct but the 95 ka24 a/c setup cannot be made to work with the rb20 computer. the ka a/c has a ac switch, cut off, and 2 wires for the triple presure that talk to the ka ecu and lets it know when to turn on and off. on the rb ecu all you have is the line for ac switch and ac cut off. there is no wire on the rb computer for an a/c thermo or triple presure switch.. i'm not sure how the earlier model 240 a/c setup is but is there a way to get a presure switch or any other part that will turn the compressor on and off and be safe? I'm goin to try and find an rb20 ac diagram and see if it makes more sense.

No, that's not correct. Go back and read those links you posted again. Those pressure switches are fail-safes to protect your system if it is over or under pressurized... they do not control when your compressor cycles in normal operation. That is what the thermo control amp does. I have it connected (but without a compressor yet) and the RB ECU controls idle-up and idle-down perfectly when the AC is turned on and off. You are correct that there are some extra things that the KA had, but you won't need them for the RB. RB setup is simple and very capable of working with the S14 system.

It sucks that I have not been able to prove this with a complete working system yet because this comes up again and again and again... summer is almost over up here and I have not had any time. I am 99% certain it will work with the compressor installed tho.

Post by **lyon23** » Sat Jun 12, 2004 7:41 am

wulfgang on ur diagram you have a a'c switch and an a/c switch cut off. I connected both of those to the rbecu and yes it does change the idle as to compensate for the a/c but it does not turn my compresor on. now on ur diagram you show 2 a/c temperature sensor on 2 diferent plugs for the rb are those the ones that take up the space for the presure switch? I tried switching both of them around and still my compresor does not engage.... I put it back to work with the switch for the mean time it's hot down here in florida.

Post by **Wulfgang** » Sat Jun 12, 2004 7:41 am

If your engine idles up and down when you switch A/C on and off then there is probably a wiring problem after the ECU. The signal from the ECU goes through the dual or triple pressure switch, iirc, so you should check for continuity across that first. That switch should always be closed.

Or, you could use a 1M resistor to +5V on the ECU (power to the MAF maybe) to pull pin 9 high and see if the ECU is pulling that to ground when A/C is switched on. If that pin goes low and the A/C relay does not click, then something is going wrong between the ECU and relay.... probably the pressure switch.

Btw, where is your manual switch connected?

The two temperature sensors you mentioned are not needed at all... they are used for the fully automatic A/C that was in some Skylines.

A/C install how to

A/C install how to

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