A/C not cooling at all?

Hi there,

I’d really appreciate your help with the issue below.

Date: 19 Jul 2025

The vehicle listed above is a Renault Mégane III DCi 2013 (Diesel, manual).

General info and tests performed:

A – I recently did an oil service (oil & oil filter). It was a bit challenging to remove the oil filter, which is located close to the AC system.

B – The AC was working well just before the oil service. However, a while back I had noticed that the cooling performance would sometimes fluctuate (getting weaker, then returning to normal). I’m not sure if it’s just a coincidence that it completely stopped working right after the oil service.

C – I found one of the pressure switches/sensors (see Pic 1), which I believe is the low-pressure one. I disconnected and reconnected it to ensure proper contact, but there was no improvement.

D – I’m not sure where the high-pressure switch/sensor is located. Does anyone know? Should I even be concerned about it at this point?

E – I tried the “bypass test” on the pressure switch/sensor by linking both poles with a wire (see Pic 2). The clutch did not engage, so the condenser didn’t start at all.

F – I still need to check the fuses with a multimeter. Do you think this could be the cause? I’m really hoping it’s just that!

G – I noticed a part (see Pics 3 & 4) on the lower left side of the condenser that’s covered in old oil/fluid. I don’t believe it’s from the recent oil/filter change, as it’s quite far from that area and looks old. Does anyone know what part this is exactly and where the oil might have come from?

I’d greatly appreciate any advice or thoughts on this.

Thank you!