Which of the 3 wires for AC Pressure Sens.
 

Is the 0-5v reference wire that talkes to the PCM?

Thanks

17 GY 2700 A/C Pressure Sensor 5-Volt Reference

Service Information

Nope, wrongo. That schematic is for an 2005 Cobalt...disregard if you have a later model as pin 17 is empty. Wrong one anyways, it is pin 26 on a 2005:

26 OG/BK 380 A/C Refrigerant Pressure Sensor Signal


Now which one is it on my 2007?

I dont know what pin number it is but on my 06 on the blue plug that goes to the pcm (the top one) its the red/black wire. Should be the only one in the harness.

http://img571.imageshack.us/img571/6410/acsensor.gif

Here's the info on the 2007 Cobalt A/C Refrigerant Pressure Sensor
LE5/LSJ engine:

Pin Wire Color Circuit No. Function

1 BK/WH 2751 Ground
2 GY 2700 5-Volt Reference - 1
3 OG/BK 380 A/C Refrigerant Pressure Sensor Signal

L61 engine:

Pin Wire Color Circuit No. Function

1 BK 6256 Pressure Sensor Low Reference
2 GY 6255 5-Volt Reference - 1
3 RD/BK 380 A/C Refrigerant Pressure Sensor Signal

Below is the schematics of the A/C system. Sorry, it's a bit blurry. If needed, I can get a bigger, clearer pic of it.

http://img806.imageshack.us/img806/4212/acsensorpcm.jpg

Well done 5hizn1t, that wins the thread.

OK.. I"m curious.. what was the point of this exercise??

The point being was to use the 0-5v reference from the AC pressure sensor as a tap to log wide band through the basic version of hp tuners.

Is that the wire that I need to put a toggle switch on??? I've been trying to figure that one out for a couple weeks now!!!!

PM me details please!!??

Yes, that is exactly it.

Crawl underneath, cut the orange/black wire coming from the refrigerant pressure sensor (small hands help) and splice two longer lengths on each cut end. Run those longer lengths to where you want your switch to be.

Get a 2input/1output switch, mine was actually 120v rated but works just fine.

Connect orange/black going to PCM to output on the switch.

Connect orange/black from AC sensor to one of the inputs.

Connect WB 0-5v output to the other input on the switch.

Voila, AC or WB logging but not both :cssNET:

so any three way toggle will work??

Yep, mine was actually 120-240v rated but flows low volts through it with no degredation.

I'm guessing it's just a signal wire set up, so voltage might not be as much an issue..

Dude.. I can't thank you enough!!! My tuner guy has been so busy that he hasn't had a chance to get me the info for that switch set up. Many thanks!

Sorry to bring this thread back up. I have 3 way toggle switch, if I hook my Wideband on toggle switch where I hook up ground wire from Wideband to where ?

Iirc, my WB ground wire is terminated to a bolt on the passenger side interior fuse panel.

I did that and it's a no go. Could it be blown fuse for A/C ? Or A/C turn off in my PCM ?

I have an 06 and I did checked my wires from A/C pressure sensor. It's Red/Black and I did what you did but for some reason it's not turning on. I use 1 wire from A/C sensor plugged to the top of the Rocker Switch, 1 wire go back to PCM go back to PCM go to the bottom of rocker switch, 1 from Wideband go to the middle of rocker switch, then last ground wire from Wideband hook on the metal. My Wideband still not turned on, it's AEM UEGO Wideband.

When you say still not turned on, do you mean as in no power whatsoever?

Where are you getting your 12v power from?

The AC sensor wire you need to tap is but a 0-5v reference, resisted from a constant 5v power that you dont lol...I know this because I tapped the 5v constant first and couldn't figure out why my gauge read just fine but in HPTuners it was full lean. Anyways, tapping it all properly is moot if you don't have a 12v supply.

I tapped my IC pump power for the 12v, which itself was running off a spare fuse in the engine bay fuse box.

I use 12v from power outlet but can't figure how I hook that up to.

Which power outlet?

And does the gauge light up? Or is it dark?

I had tried to do rocker switch with 5 pin relay, I can't get it work right. I attach Wideband ground wire to 12v ground wire n 1 go to 5 pin relay. It won't work, I took off from 5 pin relay and hook on rocker switch then it turn on. I did 5 pin relay hook on to rocker switch and I can hear click when I turn on rocker switch. It's a PAIN IN THE ASS! I am trying to figure out how ? Do I need to have ground wire from A/C pressure sensor ? I need to have wire diagrams to show me how to do this and get it working.

I did top power outlet. I custom made rocker switch to go there.

This is GREAT! I will do that today! Alittle confused with Rocker Switch, White go to the Top, PCM go to the Middle, A/C pressure sensor go to the bottom. Right ? Just double check!

Your show Orange/Black but I checked mine is Red/Black from A/C pressure sensor. Mine is 06.