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A/C with EMS on ST185

Tue Aug 31, 2004 8:41 pm

Just wondering how you guys setup the A/C (those that kept it) with your standalone. My Link Plus only has one input for the A/C idle-up, and I know that there are 2 leads for the A/C system - AC Magnetic clutch and AC amplifier?

Thanks -
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Tue Aug 31, 2004 9:58 pm

Sorry bro - removed mine :(

Wed Sep 01, 2004 12:00 am

You're doing a ground up wiring job? If you were looking at the stock harness to the ECU...I think there was only one "A/C request" that was presented to the ECU/EMS.

I don't think the ECU should be controlling the A/C mag clutch...something else should. THe EMS would not know when to cycle the compressor on and off right? So...I am thinking that we are missing some other A/C circuit in all of this.

just my $.02


Wed Sep 01, 2004 7:14 am

I am mating the original harness to the Link ECU, and running new wires when needed. According to the ST185 pin-out, there are 2 wires for A/C.

I think the ecu gets a signal when the magnetic clutch is engaged - telling the ECU to up the idle. The other wire comes from the amplifier-not 100% sure of its purpose. I've heard of 2 stage setups where the A/C system tells the ECU to idle up, then waits for a signal from the ECU to continue. Maybe the ST185 functions in a similar matter?

Wed Sep 01, 2004 2:45 pm

Now that I think about it....you must be right. I think the way the AEM had it setup was that it bumped up the idle when the clutch was engaged AND it had the ability to shut down the A/C when say....RPM, Kpa or TPS was over x. Therefore, it must have an input and an output right? Funny, I don't remember seeing that.

Let me look into this more.

Wed Sep 01, 2004 4:46 pm

Thanks - any info is greatly appriciated.

Thu Sep 02, 2004 2:35 pm

Ok...look at this diagram...

Do you see pins AC1 and ACT?

AC1 is the input. It's being tapped off a wire feeding the mag clutch relay. It does not turn the mag clutch on or off....it just tells the EMS that it's on. This is how your EMS will know it needs to bump up idle. ACT is feeding the A/C amplifier. Now, I am thinking that if you were going to kill off your a/c at say....anything over 15 psi or 6k rpm...this is the output you'd use to do that. I think they are both sensing and outputing Grd signals....but don't quote me. hehe


Thu Sep 02, 2004 4:56 pm

i have A/C with my TEC3. the wiring was done with Ricky B's PnP box.

Thu Sep 02, 2004 6:46 pm

When you look in your Electromotive software, what kind of inputs/outputs are you using for your A/C. Does your TEC3 bump up idle when the mag clutch is engaged?

Tue Sep 07, 2004 10:36 pm

i have a PnP box so i don't know if the tec3 is bumping up my idle. idle does go up when i hit the AC button and it can be adjusted via the AC idle valve in the engine bay. under the software, there is a section where it says, A/D input control #1, Enter amount of idle RPM to incerease under load. i have it set at 150 rpm. i guess i'll mess with it one day and see if the setting does anything.
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