AC compressor NOT starting. Relay is not kicking in.

[oyvind]

Hi,

A few months ago I bought a used 2012 Peugeot iOn. I am pretty sure the AC was working in the beginning, but now the AC compressor won't start. I checked both fuses, #10 under the bashboard and #16 in the front compartment, but they are OK. I also tested the AC compressor relay, and it works (front compartment, left side).

When I try starting the AC I cannot hear a click from the compressor relay. I've also tried measuring the control signal, but there's no response. For the instrument panel it appears that everything is working, but I get no cool air. I have remembered to set the temperature to cold.

Any ideas? Are there any fuses or relays I may have overlooked?

 

[siai47]

Yes, there are more fuses. However they are in the battery pack and are connected to the high voltage DC supply. There is one for the A/C compressor and one for the PTZ heater in a compartment accessed through covers on the bottom of the pack. I think it is time to go to the dealer to have him diagnose the problem. If the fuse is blown, then there is a problem with the compressor or its internal inverter. Although you could do it, and it is accessible, you don't want to be digging around in the High Voltage compartment just to confirm some other problem. If you really must dig around, be sure you have complete knowledge of what you are doing and be sure you remove the high voltage service plug (under the front seat) before starting your work. The factory service manual doesn't even go into detail on the internal bits in the pack as the dealers are forbidden to open it. Even though the power to those two fuses is not available when the car is not in the "ready" mode, safety is paramount if you are messing around inside the pack.

 

[oyvind]

I am not going to mess around with the high voltage stuff. I would leave that to the professionals

Anyway, I have reason to believe that this is a low voltage issue since the compressor relay is not getting 12 volts when I turn on the AC. So the AC compressor may very well be working as it should.

I realize there is a typo in the title. Should say "AC compressor NOT starting"

 

[kiev]

i would guess it's likely low on freon, there is a low pressure cutoff such that compressor will not come on if the system is low. Easy to check with a set of gauges and add some if needed.

 

[Don]

Low Freon in an automotive AC system is pretty common, as they use a mechanical compressor which has an output shaft with seals that eventually leak. Our AC compressor is a sealed unit similar to the one found on refrigerators and household air conditioners, so there are no seals to leak - If such a system is indeed low on Freon, there's a much bigger problem and something far beyond and DIY'er to fix

Don

 

[siai47]

One final thing and then I will sit back and relax. The oil used in the A/C system is different than oils used in other common automotive systems. This is because of the dielectric properties required to ensure the motor winding insulation isn't damaged by the oil. I remember reading about this in the service manual and I think they were even concerned about damage from residual oil that could enter the system from a gauge set that had been used on a system with conventional oil. A little overkill but----. On one of my I-MiEV's there was a fitting welded to the condenser that had a small leak. You could see some dirt around the fitting that was attached to the slight oil residue. It never caused the system to stop operating, but it was still a very slow leak. I would take the trip to the dealer for this one--first to verify what's gone bonkers in the system and then to not compound the problem by having someone introduce another problem that might show up later on that could cost more expense. Just my opinion (and I am not shilling for dealers) but probing around a completely alien A/C system by a normal A/C shop could result in major headaches and a walk of shame to the dealer in the end !

 

[sventchik]

also one remark..... could be stupid, but it happens sometimes....

To make the A/C working, it's not only pushing on the A/C button, you also need to have the ventilator turned at other position than "off".... and the position is not clear marked or visible

May be it's the case

 

[PV1]

Yeah. The lowest setting is Auto, then Off is one click up. That seems to catch a few people.

 

[kiev]

Good point to check the fan setting (to other than OFF).

Even though the compressor may be of the sealed type, there are plenty of lines with threaded fittings and valves, each of which is an opportunity to leak freon. Leaking freon is a very common failure mode of automotive AC systems.

A new set of refrigeration gauges could be found fairly inexpensively if there was a concern about oil contamination, but the state of the system pressure can only be known by checking it with gauges.

The label on my 2012 calls out 11.5 oz of R-134a refrigerant (freon), and the lubricant oil is MA68EV.