Yep the solenoid is driven by a PWM 12V signal. I tested my compressor by unplugging the solenoid connector and powering it from a power supply with the engine running. I slowly ramped up the voltage, but didn't exceed ~10V which was enough to see sufficient cooling and determine that the compressor was OK. How did you go with yours? Make sure you watch part 3 btw.

Hey mate, Get yourself a scan tool if you haven't got one already and check out those engine codes, that'll give you a good hint what the problem is - the engine management is most likely preventing the AC turning on due to a fault. By the way, you wont hear the AC compressor click like you might be familiar with, since the compressor is a variable displacement type - these don't have a mechanical clutch. Coming out of the cooler months, you've probably only noticed it's an issues since we've had some warmer days recently. I'm guessing it hasn't been working for a while. Work out what the engine faults are before touching the AC system - chances are there's nothing wrong with it.

@@Justfixitmate Thanks mate for your quick response and the info. Yes, I do need a scan tool, I did some research into this a while ago but it sounded like installing the software on the computer could be very problematic (this was for Lexia/PP2000 scan tool). Not sure if a generic scan tool would be much help. Do you have any suggestion for an appropriate tool? That's good to know about the compressor too, I was worried it might have packed it in. Sounds like it might not be as bad as anticipated. I know a previous mechanic just over a year ago told me that some sensors were on their way out, maybe its one of them causing the issue. Yet the mechanic said there were no problems with the car when it was serviced (and scanned) a few months ago though. Will do a bit more research on the scan tools.. hopefully can get this problem sorted this week. Cheers.

I bypassed the BMS and powered the compressor valve directly - see my other comment below.

G'day, to me it sounds like you may have insufficient gas, or an overcharged system. This could result in these kinds of symptoms. A faulty pressure sensor I suppose could also lead to similar behavior. The ECU will turn off the compressor if the pressure detected is too high or too low to prevent damage to the compressor. If you are sure it has been correctly charged with gas and oil, then perhaps worth checking the pressure sensor. I believe they're threaded onto a shrader valve and can be replaced without discharging the system. My older scan tool didn't detect the DTC relating to the thermostat housing by the way. However if there is an issue with the thermostat housing or cooling system, you might experience the thermo fans running after ignition is turned off.

@@Justfixitmate Thanks for the reply! Yesterday afternoon we checked the amount of gas. The factory specification was 450 g, and the filling in the car was 439 g. We added 450g to the car but the error is still there. I will try to get a pressure switch today. I will report the results!

​@@SchafflerFerencBro died before he could report the results. R.I.P

I remember having a similar issue with my 307. It was just a bad contact in the lamp assembly due to moisture/corrosion in my case.

Hey mate, When I had this issue, my scan tool wouldn’t pick up the thermostat codes. I needed to use peugeot planet. But it sounds like you’ve checked that all out. If your compressor is a variable displacement type like mine, it's a bit more difficult to test the compressor. Do not directly connect to 12V, as you could burn out the solenoid and possibly your BSI too. These operate with PWM / variable duty cycle. To test mine, I completely unplugged the vehicle loom and connected a benchtop power supply to the two pins on the compressor. By limiting the current and slowly bringing up the voltage I was able to hear the compressor sound change and feel the cold air inside the cabin. I didn't exceed 6-7V from memory current draw was a few hundred mA. I only tested for a very short period too. Did you install a new condenser or one from the wreckers? I’m pretty sure the receiver drier is integrated - was this checked out by your AC guy - could be freezing up? Do your AC lines get cold at all? Is the correct amount of oil in the system?

@@Justfixitmate Okay so 14v without plug being connected to bsi connected on pin 4 connected it dropped to 11.8v about to test from compressor connection, but ohms was 12 from bsi connector to compressor

@@Justfixitmate 12 ohms at compressor as well

​@@GeraldBirkett 12 ohms sounds about right. Your best bet might be to get your AC guy to measure the AC line pressure with gauges. That will tell you if your compressor is working. So they re-gassed it, said there were no leaks, but it didn't work and couldn't tell you why? Did they then evacuate the system after that or leave it charged with gas? Might be worth taking it to a different AC guy.

@@Justfixitmate kept it charged with gas, I asked them too and they did show me the measurements on the machine where high line was and the low line was, but the compressor wasn't kicking in, was thinking it was a loose connection, but I've gone over it myself from pressure sensor and the volt was the same as what you pulled as well so I know the system has the right gas in it and also checked on diagbox and it was 8-9 bars and that's within range of the compressor will cut anything under 23 bars so it should be turning over also I measured 14v at the compressor plug end connector while running as well so if there is power going all the way to compressor it should be turning over.

G'day, if it has dual zone climate control, could be issues with mixer flap stepper motors in the heater matrix. do you get cold air in the rear passenger seats?

@@Justfixitmate the car dont have dual climate only the front outlets, also no rear outlets

Since these video a few years back I recently had a leak in my AC system. After wasting money on a few visits to a "professional" I was still losing gas. I ended up finding the leak myself - It ended up being a small leak at the firewall at the connection to the evaporator. Difficult to visually check due to the location. Replace the o-rings and had re-gassed - has been good for quite some time now.