Ecumaster forum

Hey guys for those who moved to 1.51 you'll see there is A/C control now.

I have everything hooked up from the factory (A/C switch, then A/C Clutch).

For some reason, if I leave it as is, the relay doesn't kick over when A/C is activated. So I went ahead and reversed the polarity (via software) and the compressor kicks on, but WILL not kick off if I press the A/C switch. Any ideas?

pressure switch?
trinary switch?
what car is it?

sometimes you need to selsct the "INVERTED ANALOG" input option

gregpe wrote:pressure switch?
trinary switch?
what car is it?

Pressure minimum is 0.

R32 Skyline GTST.

RHD
I tried inverted, it kicks the compressor over, but it won't shut off.

Have you checked whats happening on the analog input under log when pressing the ac button? You may need pull up / down.

HI
What is your activation input?
is it working? you should see when is on and off? in older cars this is going via trinary switch if pressure is out of range ( below or above) wont connect switch to input to ecu..

I'm using B20 as my in, and Aux 5 (I think?) for my output.

The problem that I'm having, is it won't come on at all, but if I click "invert" it comes on, but won't shut off.

What do you mean by "see it"? Is it on the dashboard of the EMU?

i mean activation input. is changing status you with pressure or button? perhaps need pullup resistor... if is switching to ground ground..

I just took a look at it, and it is not changing at all on the bottom.

Guess that is gonna be the first step

you might need to use a pull-up resistor so there is a voltage signal then when the switch is activated it pulls the voltage to ground.. i needed to do this on a supra the other day.

2.2K between the analog IP and any 5v or 12v power supply

when i was talking about the inverted input be careful there are TWO options for inverted, one ids the box you can tick but that inverts the OP not read an inverted IP if you use that then all your idle adjusting parameters will be active when your AC is off, and not active when the idle os on etc!!!

The other inverted option is on the ANALOG INPUT selection.

Still no luck.

I haven't really messed with it much though. I've uploaded the diagram from the service manual. I can't tell whether it runs a power or ground circuit though, but it is wired up correctly.

From memory pin 46 is input, and pin 9 is output.

Looks like your AC clutch is controlled by +12V not by the ground...

Just a quick update for anyone doing this.

My A/C signal is GROUND, not power. Still haven't gotten it to work, but finally had some time to look into it.

Okay, since I"ve been working on this and it's making me angry

First and foremost, I have pressure Minimum to 0. The reason is because the Skyline uses digital climate control (DCC) so pressure is already worked out.

I have my input (IP) as B11, and Aux 2 as output (OP).

Aux 2 is good, if I click invert (making it a ground signal) it forces the compressor ON regardless of the DCC on or off.

I grabbed a test light, and I put one end to Ground, and the other to pin 46 of the ECU with the DCC On, and nothing happens on the test light. If I tapped one end of the Test Light to power, and the other 46 with the DCC On, and the test light comes on. So that means that the DCC sends a GROUND signal to activate the Compressor (via relay of course).

So, the software side of things, if I put it on B11 IP normally,(DCC On) nothing happens. If I swap it over to B11 IP INVERTED the Compressor will come on with the DCC On, but will stay on afterwards regardless of DCC position.

In order for the Compressor to turn off, I have to apply power to B11 and keep it there. The moment I remove it, the compressor kicks over.

So keep in mind, Aux is Set as normal, not inverted whatsoever, so I'm sure my Aux 2 is setup correctly.

I feel like I should leave B11 Inverted, and add a diode to it, and maybe it help it click off? I'm not really sure, I just want A/C working

RHD wrote:you might need to use a pull-up resistor so there is a voltage signal then when the switch is activated it pulls the voltage to ground.. i needed to do this on a supra the other day.

2.2K between the analog IP and any 5v or 12v power supply

when i was talking about the inverted input be careful there are TWO options for inverted, one ids the box you can tick but that inverts the OP not read an inverted IP if you use that then all your idle adjusting parameters will be active when your AC is off, and not active when the idle os on etc!!!

The other inverted option is on the ANALOG INPUT selection.

I'm sorry, I can do wiring, but this isn't really my cup of tea. I think you are right, after doing some research on pull up resistors, I found out it's pretty much what I need, and not a diode. I need something to show it power when there is no ground present, but when the ground switch comes on, it needs to be able to overpower the power signal, but not enough to cause a short. I'm going to pick up some resistors rightnow

Bingo, pull up resistor worked! Thanks so much for everyone's help, but especially RHD's.

I used a 2.2K resistor, soldered it in between two pins, and voila. I've got A/C