How to bypass a 3-pin AC pressure Switch in a car as well as determine the pinout

[@bryanclayton7008]

very good idea. Just checked a 2013 pathfinder high pressure switch and you were correct, middle pin was signal, I found the 5v ref and the other was a good ground. Used 2 AA batteries taped together with clips taped on battery ends. Thank you!

[@TomDaghdha]

Cheers - just got my Toyota AC pump running again. 5V and Gnd on the outsides and 3.3V from a pair of AAs up the middle clears the fault code.

[@jefferystone1]

Just did this and it worked great (I used a coin cell battery 2025 3v). To determine which wire is ground, using each wire of the 5v/ground pair use continuity of each to battery ground - the one that beeps is ground. The other will be 5v.

[@Tarm90]

you mean a 2025 battery?

[@jefferystone1]

@@Tarm90 Yes, 2025 - edited orig comment - thanks

[@Tarm90]

@@jefferystone1thanks Jeffery.. so just to confirm how did you test which each wire was?

[@woodygotem]

thanks for the video, it was hard to figure out how to bypass the switch, didnt think i needed some double a batteries lol

[@mikehill4551]

I'm doing some troubleshooting on my car and the AC compressor connector access requires removing the AC condenser (crazy design). This should be a quick way to determine if it's the pressure transducer or the compressor. Thanks!

[@juanrojano7966]

Thank you for your time to help whit this matter appreciated.

[@luisdlc21]

Wouldn't be better to bypass the signal with the 5 v reference?

[@viper1431]

Wouldn't that give the ecu a high pressure problem which would also stop it turning on?

[@RaofEmbark]

Great video, but why not use two resistors to make a voltage devider and give 3 volts to the mid pin

[@danielyoussef6027]

You absolutely can but I just didn’t want to do the calculations as they vary depending on the current that is passing through the pins so the resistance required would vary from car to car

[@Krume79]

Excellent video, well done, a'm a little confused about yesterday's car.... On the pressure sensor 2 wires were ok, 5v and ground, but the signal wire showed 4.67v from ECM, and i do not know what to do? The compressor clutch do not engage 😢 pls help

[@woodygotem]

sigh, the ac light stop flashing in my lexus when i did this, klutch not kicking in, i guess its time to replace it

[@richardmarshall6751]

Why not just jump the 5VDC reference pin over to the middle pin? Wouldn't that also trick the system into think it is full?

[@richardmarshall6751]

OK, someone else already asked. Apparently, seeing the full voltage makes the computer think the ground is lifted, which would make the signal go to the the full V-ref (5VDC), and the computer interrupts this as a fault condition. It's too smart for its own good! Use the battery method, as shown.

[@DownloaderVideo]

The computer is looking for a voltage between 3.2 to 4 volts. Anything below or above means under pressured or over pressured system which it is a fault condition so the compressor will not start.

[@heitorvieirafilho2643]

Thank you so much God bless

[@inintuk7433]

how would it recycle?

[@Tony-tk4ht]

my signal and vcc is 5 volts. what does this mean?

[@rcypert]

Mine as well.

[@D_M_S_4]

Will 2 triple AAA batteries work?

[@GrzegorzDurda]

yes it's just for voltage signal.

[@byronlee6486]

Could you just jump the positive output to the signal?

[@danielyoussef6027]

Technically you could but you risk blowing a fuse or relay for the ac system because the 5v reference is high amperage and the signal should be between 3-4v and very low amperage

[@siucbset]

Maybe: Maybe but most likely not. Depends on manufacturer. If there is an open on the ground side then the signal sweep could read 5V so the PCM might have 5V marked as a fault so this could flag the circuit so the PCM might not turn the compressor on.

[@luxarcadia2209]

Dose 4v and 100ma is fine​@@danielyoussef6027

[@pastorkristoffer4074]

You gonna ruin so many compressors

[@danielyoussef6027]

Why is that?

[@josepena1046]

Well done