I had a 93 Honda Civic with a R12 AC system that lost its gas. Paid to have it converted to R134a and found it hopeless. I then took a punt, bought the equipment and filled it with air duster. It was incredible. My face would often freeze. I miss that car. Sold it in 2020.
Did this on my Hilux Surf a few years ago (WD40 branded air duster uses the same gas BTW). It would freeze the evaporator over when the blower fan speed was set too low with a high humidity, so I'd say it was effective. That's car now has R134A in it as I did an engine swap and had to have new hoses made anyway. Those can taps are as sketchy as they look, had mine crack after a few goes, if people plan to do this, just be careful when puncturing the can. I've since switched to HyChill for my other cars as the taps for those are much less sketch, you can pretty confident the gas is clean and it has similar benefits to R152A in that you need much less of it (by weight) than R134A.
By the way, I have recently replaced the R15 fan resistor but the first speed never kicks on with the AC on and it's been pretty hot these days here in Portugal, so I would expect it to turn on. The resistor is fine as far as I can tell, at least it measures the correct 0.2 Ohm resistance value.
will need to study the wiring diagram and check the relevant relays / switches etc. You can find it by searching for W124 ETM. It is free, no need to pay for it. If someone asks for money, keep searching.
I might use this to check an R12 system for leaks. And. then I’d fix the leaks, and refill the system with actual R12. The 134 conversion kits don’t seem to be manufactured correctly these days.
