15/07/2026
Another day…. Another air con re gas, or so we thought.
This is a long one so strap in.
Ha this 2021 focus with under 11k on the clock come in with air con not working, just a simple re gas we thought, well I was wrong.
Get it strapped to the machine, get in on cycle to suck out the gas, vacuum test and sq**rt in new gas…... well that where the problems started.
Yo see, this focus takes 480g of gas to fill it up, we managed to suck out 810g, that’s almost double what should be in there. Crazy times.
After it did its thing, start the car, no compressor running. Damn.
So onto test. Plug In diagnostic, nothing, won’t communicate with the system, so onto manual testing.
Check fuses, all lovey, check power to compressor and zero. So get the power probe out, give the compressor some power and it kicks in, no cold air but clutch works…result.
Something isn’t right, test the pressure switch, all good, but still no communication with air con system.
So test earths, all good, test everything 2,3,4 times still no power.
This has me scratching my head. So chatting to customer he mentions it’s only done few hundred miles the year, and needs a way to keep it charged, that’s when it hit me, it goes flat??? Let’s look at the battery. Brand new (5 month old) battery fitted by main dealer. So I run a proper battery test, only 33% charged. This can’t be right, it’s brand new. So test the alternator, literally trickling power in, not good.
So I have another brain wave, these smart charge battery monitoring systems are very sensitive, I wonder……….. and I wondered correctly. The dealer fitted a new battery, but didn’t code it in so it was charging the new battery as if it was old old buggered one.
So I code battery in and bosh I get communication with the air con system, fault for pressure sensor (not surprising as it had almost double the gas) I clear the codes, fire the beast up and the compressor clicks into action., 5 sections later I’m sat in the car freezing my knackers off.
Just goes to show, never assume because it’s warm it just needs gas.
Never assume the person (dealer) that fixed it before you did it properly.
Never assume that plugging into a diagnostic will find the fault, nothing replaces good old testing and fault finding.