My A/C would only work on speed 1 and sometimes 2. I followed these instructions. R12 feels amazing.



Category Five Motorsports

Power-FC A/C MOD

This mod will enable your air conditioner to work when installing a Power FC in FD3s. This will also fix the problem of the a/c not working on one or more of the fan speeds.

The reason the a/c does not come on is because as the car ages, the ground signal going to the ECU’s (wire 1E) is receiving a fuzzy ground signal. Some cars have no problem with the signal, but some do; the last FD I worked on the a/c did not work on any speed. My mod will interrupt the signal going into the Power FC and redirect it through a simple Bosch relay. This will also let the Power FC still control the IAC and switch the a/c off at wide open throttle.

Locate wire 1E (Violet wire) - it is the third wire from the end on connector one. Cut the wire 2” from ECU. On the harness side you will hook 1E to (86). On terminal (85) on the relay will go to ignition +. Terminal (87) will go to 1E that was cut on the Power FC side. Terminal (30) will go straight to chassis ground. Now when your a/c is turned on, it will receive a nice healthy ground. If you have any questions contact me via email.

Freddie@catfivemotorsports.net

 

I just did this and it worked . I now have ac on all settings .

 

Sweet !

 

have you ever encountered this . I'm trying to figure out if this is the power FC , or some other underlying issue

my fans work at all speeds . BUT my AC controls DO NOT WORK I cant switch hhere the air comeso ut , I cant turn on the AC nothing lights up when I press the AC button , or the recirc button , nothing works I thought it was a faulty control unit so I tried another one form a friend that was working and nothing did hte same thing . its as iff its not even recieving any power , the hazard lights work , and the cluster dimmer works . the fan speed works , but the temp , nor the directional flow controls work .

I'm wondering if this is caused by the Power FC . or if this is another underlying issue ..

I've checked all the fuses they seem to be good . I'm going to check the relay hope the relay has something to do with the controls .

Oh also I tested all the equipment manually using a test light nad they ALL OPerate
so its not that they are broken

 

Also my little fuse cover lost the label , I thought I read one fuse that said hazard /ac in whats left of the paper . But Now I'm doubtful . as I'm reading the FSM , Wiring diagram , Z68 , it says that the rear Wiper fuse is what feeds power to the AC controls ? is this correct ?

 

I got it figured out I just spammed this thread for nothing sorry!

 

What/which bosch relay and any pics?

 

Those relays are all the same.

 

"On terminal (85) on the relay will go to ignition +." Is there a certain location or color I'm looking for? Just want to confirm and clarify. Thanks. Would be nice to have all 4 AC settings, than just setting 1, lol. Thanks again.

 

I use one of those Greddy turbo timer harnesses that have a few wires hanging out. One is switched ignition that I use for my water injection, the other is Hot and I used that for the relay.

 

I've got these issues with my 93. However, I do not have Power FC. Would this fix still be implemented? If so, does anyone know a thread with more instructions or pic walk through?

 

Here it is.

 

pictures?

 

This is not kinder garden or grade school.
That is what the FSM is for, to find where things are and how they work to some degree.

You either have the knack or pay someone to do it.

 

As mentioned in my original question - these instructions all reference having a Power FC mod.. which I do not have. Hence why I am looking for more details because these instructions are very specific to the wiring of the PFC. While I have the same symptoms - these might not provide the same resolution if they are specific to PFC issues... so no, I am not asking to be taught like a grade schooler, simply asking people broader questions to clarify the original op's posting. Thanks

 

Applies to the stock ecu the same as the PFC. The wiring change will relate to any ecu that uses the AC switch and fan speed in the same way as stock, and controls the idle speed.
Only would be different if the AC was greatly modified over stock.

The AC could be wired to not even connect to the ECU as the ecu connection is only for ISC control.

If you understand basic DC circuits and read the manuals for the AC, then you would understand.
If you do not know electronics or basic wiring, do not try it alone.

 

I just follow the op's instructions and it worked perfect for me. My pin 1E was black with a yellow stripe on my 93 touring, but it worked just the same. I had a/c in fan speed 1 only before the mod. Now after the addition of the relay all 4 work great. Very good stuff!

 

I performed this mod and the AC is working on all 4 settings. Still running into some issues that I don't think are necessarily tied to PFC. I will be posting further about this once I get them well documented.

 

I am considering doing this mod but after thinking about the logic of the relay, I'm wondering something: Why not just splice the 1E wire directly to a clean chassis ground rather than have it switch to the chassis ground only when the ignition switch is turned on?

Maybe I'm missing something in the logic? With this relay mod, when the ignition switch is off, wire 1E coming out of PFC is disconnected from the ground, and when the ignition is turned on, wire 1E is then connected to the chassis ground. Without the relay mod, wire 1E is always connected to a chassis ground (albeit a fuzzy one).

So wouldn't the more logical solution be to simply splice or cut and connect wire 1E coming out of the PFC directly to a clean chassis ground?

 

Yes you are missing something, not understanding how the circuit works!
Go back and study Freddy's mod, and also look at the manuals FSM Section F and the Wiring manual for the AC.

Your way is fine if you want your AC running 100% of the time.

HAHAHAHA!

 

Ah - I see what you're saying. I was thinking that the 1E on the harness side was going straight to chassis ground, but it actually is only switched to ground when a signal is activated to turn on the AC compressor through a myriad of circuits.

Thanks for the clarification!

 

I concur with previous posts, just follow the directions as posted. Took about 1 1/2hrs.

Thanks much Freddie.

 

Gents,

I tried to reach Freddy, but found that his email no longer works. I'm hoping that someone can drop some knowledge on me ? My question is as follows:

I plugged in a bosch solenoid as per the instructions, and the solenoid clicks when I hit the AC button, the AC light illuminates, and the cooling fans come on (I have them set way low on the PFC when AC is active).

I'm still not getting the compressor to engage however and I've tried troubleshooting but I'm stuck: I have the pressure sensor jumpered (system isn't charged right now) and i can get compressor engagement if I jumper the AC clutch solenoid (see attached wiring diagram). So, my thought process is that the AC compressor clutch solenoid isn't getting a ground from the PFC.

It appears that the control wire for the solenoid terminates as an input at 37 into the PFC (which is pin 1L). This is where my understanding breaks down - how does the PFC control the solenoid if pin 1L is an input?

Thanks in advance for anything that you all can offer

Aaron

 

How did you get on with this? I am having a similar issue myself.

I live in Australia and have a s8 (2001) fd with a power-fc. The wiring diagram/pinout is a little different, but AFAIK, the wire colours have remained the same. I tested the whole system extensively as I thought my compressor clutch was the issue. Turns out the power FC is not activating the A/C relay. I traced the wire and tested it for continuity. Everything seems fine. I am tempted to just bridge the relay in the short term as it is summer here. But I would like to know if there is a more permanent solution.

I tried the relay mod on the violet wire, but this has not helped. The fans come out and it seems as if the idle is being compensated, so surely it is not too much of a stretch to get this relay to activate.

I guess I would be prepared to either wire in another relay or rewire the current relay so it activates off the A/C switch in cabin. I can always turn it off easily if driving in a spirited fashion.

 

Still stuck! Getting ready to take the car out of winter storage, and I'm eager to get this sorted out. Maybe it's something to do with the evaporator sensor to prevent icing?