AC control wiring question

Hey wiring experts! I have an AC project and I found the wiring pin out for my 2014. However, I don't know which wire I need to tap for the AC. I need to get the +12v signal when the AC is turned on from the AC control panel. In the diagram, there is AC (pin 13) and ACID (pin 10). I have no idea what ACID is for and I don't want to tap into the wrong wire. Google search only pulls up info for lead-acid batteries.

Any help is appreciated!

 

Thanks! Looks like I should tap pin 13.

 

Depends on what this tie into needs to do...

 

I just need to get a signal when the ac circuit is active. I'm building a GPS activated switch with a raspberry pi.

 

id tap into the compressor power wire. It’s hearty and will handle the extra small load. The wiring from the switch will typically drive a transistor low or high in the ECM and tapping into that can affect its function.

 

I only need to get an input signal and also going to step down voltage to 3.3v. I don't want to run another wire into the engine bay. Thanks though!

 

You wouldn't:

 

Are those pins from the fuse panel? Those aren't easy to get to. It would be much easier to get it from the ac harness. Is the ACID pin the one that triggers the compressor?

 

No, Driver's kick panel.

No idea.

The green wire on A14 is a negative trigger. Don't know if that will work for ya.

 

what I would use, is a split core Hall effect around the compressor power wire matched to supply the DC output you wish to the compressor running current.

 

That is the A/C switch LED signal that drives the LED on the control assembly. It will read +12V with AC off and driven to ground with AC on, will not work for your setup.

 

Put a clamp on there and measure current with the compressor engaged. Find a hall effect sensor to match your desired output voltage. Even that will not be fool proof though as the compressor cycles based on pressure so it may not be running even though there is a "command" for AC. If you want a reliable way without running a wire into the engine bay, I'd use the ACID wire and redesign your project to negative trigger on the ACID signal.

 

Thank you. You guys have been very helpful! Unfortunately, the pi cannot handle negative input voltage. Is there any reason why using pin 13 wouldn't work?

 

Found this on the12volt.com. it looks like I can use a simple relay to convert negative to positive.

 

Couldn’t you simply write your Pi code to just use the inverted logic from the ACID line?

When Pi pin (AC on/off) is High, the AC is OFF.
When Pi pin (AC on/off) is low, the AC in On.

You would still need to step the +12 down, but you were planning on that anyway.

 

Setting the input pin to low still means it's looking for +volts. I've read applying negative voltage to an input pin on the Pi will damage the board.

 

I guess I’m not seeing where there is a negative voltage. Above it was explained as the ACID being at +12 or Ground.

+12 when AC is Off
Ground when AC is On

Is that not the case?

 

I'm not an electronics expert. So I'm probably confused by what's being said.

My understanding (so far) is that the pin 14 is ground 0v? When the ac button is pushed, the circuit completes and pin 14 is now at +12v?

So I should just check to see voltage when 14 has +volts?

 

I used the term negative trigger, not to be confused with negative voltage. Everything is referenced to +12V. Negative trigger and falling edge are synonymous. I can reword my statement to "falling edge" trigger meaning when the ACID signal is driven to ground (0V) use that as your trigger to whatever you want to do, there shouldn't be a reason to putting an extra relay in there to invert the signal. I'm no expert on how the PI system works, I'm used to programming PLCs and astromed signal recorders; but I'd assume you can program it to actuate logic based on leading edge or falling edge signals, otherwise it doesn't seem worth a damn as a system LOL