Peugeot 508 Aircon Troubleshooting

[ben341]

Hi all,
I was just about to try and get a quotation as I'm not sure what else to look for, but thought maybe I could kindly ask for some pointers. Car is a 2012 Peugeot 508 saloon, 1.6 blue hdi, 60k miles, basic equipment, no auto climate control (i.e. you turn it on, turn a knob and it goes - supposedly!)

The air conditioning isn't blowing cold air. I believe it was working last summer but wasn't hugely effective. No major changes since then other than what I'll describe later.

What I've done

Had a recharge from Halfords in May, they said there were no leaks
Changed cabin air filter same day after I realised recharge didn't help
Basic visual inspection of air intake under top of bonnet for signs of debris.

What I've observed:
Approx Nov 2023, air mix dial started to blow hot air when in neutral position. Dial seems to turn normally. Wondering if fully cold now = neutral? As its electronic and I don't believe it was mishandled, wonder if there could be electronic issue or problem with air mix flap/servo as seen on a number of youtube clips of people cutting open that bit and gluing it back together.
No engine codes
Air con light goes on, stays on, no flashing or immediate sign anything is wrong.
Had a look at radiator grill etc, can't see obvious damage.
I don't recall a time intentionally turning the aircon off, I just leave it on all the time, not sure if this is a good thing or not but I guess its the opposite of not being used enough.

I'm unsure where compressor is to determine if it is functioning, happy to check if pointed in the right direction.
I used to park under a sycamore tree, which has been bad for blocking the rainwater channels under windscreen. This is why I visually inspected what appeared to be air intake that is partially covered by the edge of the bonnet. I could see a small twig but nothing loads. When I replaced the cabin air filter, there was a small amount of debris and a small leaf. I tried to get my hand in there to see if there was anything more I could pull out but there wasn't. Old cabin air filter wasn't really in a bad way either.

Other issues: I have engine warning light as a result of a permanent fault code with energy accumulator that began after I couldn't start it in cold of 2022 and had to replace battery. Battery was replaced by RAC and is a Varta, appeared to be similar in spec to one removed, certainly hope so for what it cost. Had occasional warning with cylinder 1 not contributing as much, no significant roughness in idle etc but have to keep an eye on it.

If anyone can offer any insight please it would be appreciated.

Thanks
Ben

[PaulC5]

The compressor is probably underneath the alternator, when the air con is switched on you should hear it click as its clutch engages. This also needs the cabin fan to be running and the engine fan to run on/off to keep the refrigerant pressure right. When you use the normal heating, when the temperature dial is used does the air go from hot to cool showing the flap moves ok ?

[GiveMeABreak]

The cabin fan has nothing to do with the radiator fan and does not need to be on for the A/C to work , but the radiator fan always runs of low speed when the A/C is activated.

Always best to leave the A/C on where possible as it maintains the seals on the A/C system - periods on non-use cause the seals to perish and that can cause leaks.

I suggest you have it pressure tested again and don't go to Halfords - they really are not the best to be honest and their knowledge is seriously lacking. You can even get a mobile service that comes to you complete with all he kit for testing and refilling where necessary.

I'd need your VIN top determine what system is fitted to your vehicle before I can comment on reduction gear etc as this depends on the system you have. Please post your VIN in full without spaces - it will be automatically masked from public view after submitting your post & will only be visible to staff.

[Sloppysod]

I'm not sure, but I would have thought halfords would have told you your compressor is stuffed, and offered to quote for a replacement!
With the engine at idle, there should be a slight increase in engine rpm when the aircon is switched on.

[LedZep]

Had a recharge from Halfords in May, they said there were no leaks
Changed cabin air filter same day after I realised recharge didn't help
Basic visual inspection of air intake under top of bonnet for signs of debris.

I don't know if it helps but from my experience in 2 cases where there was no leaks of refrigerant, with my wive's KIA and another Toyota that i own, the relays of fan engagement or the circuit for AC were burnt. It's simple to check with basic electric knowledge and also check if the clutch of AC engage or if the fans rev up which of course depends on the ambient temperature. The basic principals are the same in all cars even the "exotic" equipment that may have so maybe worth a look and with just a 3-4 £ do your job.

[ben341]

The compressor is probably underneath the alternator, when the air con is switched on you should hear it click as its clutch engages. This also needs the cabin fan to be running and the engine fan to run on/off to keep the refrigerant pressure right. When you use the normal heating, when the temperature dial is used does the air go from hot to cool showing the flap moves ok ?

Thanks Paul, I'll see if I can hear a click when I have a second pair of hands to turn the AC on while i try and look for compressor, guessing the click happens when aircon is enabled on panel.
For the flap, this is what I'm unsure about. Far right = Hot. Middle/Neutral = Quite Hot (definitely heat from heater block, not just warm air outside), Far left (cold position) = neither hot nor cold. Last year I had normal operation, Right = Hot, Middle = Neither, Left = Cold, with varying degrees between.

[ben341]

I suggest you have it pressure tested again and don't go to Halfords - they really are not the best to be honest and their knowledge is seriously lacking. You can even get a mobile service that comes to you complete with all he kit for testing and refilling where necessary.

Thanks for reply, I should have clarified, I paid Halfords for the mobile service. I think his van was Halfords branded. To be honest I've been using Halfords as the guy there is the only one with a contact at VOSA that says its OK to pass my car's test with the "Engine Fault" coming on when turned on but no MIL staying on, as a result of the energy accumulator code, everyone else fails it. Says he's happy to pass that issue every year for me.

As for VIN I should have given it first, thanks VF3**************[VIN obfuscated, can be read by forum staff]

[ben341]

the relays of fan engagement or the circuit for AC were burnt. It's simple to check with basic electric knowledge and also check if the clutch of AC engage or if the fans rev up which of course depends on the ambient temperature. The basic principals are the same in all cars even the "exotic" equipment that may have so maybe worth a look and with just a 3-4 £ do your job.

Thanks Zep, I did wonder if it could be something like that and checked the manuals for the fusebox/relay layout on all the fuseboxes in the car and didn't see anything relating to AC function at all which I thought was odd. Do you think I should be looking somewhere else?

[LedZep]

the relays of fan engagement or the circuit for AC were burnt. It's simple to check with basic electric knowledge and also check if the clutch of AC engage or if the fans rev up which of course depends on the ambient temperature. The basic principals are the same in all cars even the "exotic" equipment that may have so maybe worth a look and with just a 3-4 £ do your job.

Thanks Zep, I did wonder if it could be something like that and checked the manuals for the fusebox/relay layout on all the fuseboxes in the car and didn't see anything relating to AC function at all which I thought was odd. Do you think I should be looking somewhere else?

In my Toyota and my mother's Suzuki had 2 relays for ONE fan. One relay was for the normal temperature operation of thermostat and the second was for the A/C rev up when you turn it on.So maybe a check of the fans relays helps. Some cars have separate fans for condenser and cooler with a separate relay of course.

[ben341]

With the engine at idle, there should be a slight increase in engine rpm when the aircon is switched on.

Hi Sloppy, just given it a good few min trying to look for this. No twich in rev needle, no audible change to engine speed. I also couldn't hear any mechanical noises with window down from drivers seat. Checked rad fan, it wasn't spinning with aircon on. Dash says its 21 degrees out there right now which may be a bit high but i'd guess 19-20 from feel.

Sounds like its dead to me!

[LedZep]

With the engine at idle, there should be a slight increase in engine rpm when the aircon is switched on.

Hi Sloppy, just given it a good few min trying to look for this. No twich in rev needle, no audible change to engine speed. I also couldn't hear any mechanical noises with window down from drivers seat. Checked rad fan, it wasn't spinning with aircon on. Dash says its 21 degrees out there right now which may be a bit high but i'd guess 19-20 from feel.

Sounds like its dead to me!

Unfortunately my friend, A/C breakdowns, are a headache to spot.Just search for the obvious things that you can do like blown fuse, relays (if they have, who knows), if you have knowledge and a multi meter to check grounds and signals e.t.c. Maybe there is a leak and low pressure refrigerant that halfords (i suppose mechanics) failed to spot. Maybe there is just a control unit that makes all things happen. This depends from the system is fitted and GivemeABreak maybe help you with this and what to search for. To give you courage, outside this moment we have 39/40 C, so you are o.k. At least A/C of house, cars, cafes, or wherever i go, works. Oh, i missed my opel manta when i was FREE with just window airblow and everything was nice.

[ben341]

Unfortunately my friend, A/C breakdowns, are a headache to spot.Just search for the obvious things that you can do like blown fuse, relays (if they have, who knows), if you have knowledge and a multi meter to check grounds and signals e.t.c. Maybe there is a leak and low pressure refrigerant that halfords (i suppose mechanics) failed to spot. Maybe there is just a control unit that makes all things happen. This depends from the system is fitted and GivemeABreak maybe help you with this and what to search for. To give you courage, outside this moment we have 39/40 C, so you are o.k. At least A/C of house, cars, cafes, or wherever i go, works. Oh, i missed my opel manta when i was FREE with just window airblow and everything was nice.

Yeah it seems they are a pain. I am grateful for it not being 40 degrees right now. Personally I'd just put up with the heat in the car, it isn't like I drive much anyway, car will probably disintegrate to dust before its done 100k miles. What I'm afraid of is 3 kids whining on endlessly as to how hot they are when there is still 2hrs in journey to go, that's painful! In fact it wasn't that long ago they complained they were too cold when I had aircon on and it was 30degrees outside!

Thanks again.

[ozvtr]

The cabin fan has nothing to do with the radiator fan and does not need to be on for the A/C to work , but the radiator fan always runs of low speed when the A/C is activated.

Not sure what Marc is saying here. Not sure what the is all about. Not sure if he is talking about the radiator fan or the cabin fan, BUT, both should be operating while the A/C is running.
While, typically, the interior fan serviceability is not monitored by the aircon ECU, the interior fan must run to blow air across the evaporator while the compressor is running. Otherwise the Tx valve will freeze up, causing a potential over pressure of the "high side". Consequently the air con system will not run if an interior fan speed is not selected. I.E. the aircon wont work if the interior fan speed is selected to OFF.
Unless I missed it, you didn't say how long ago you had the system regassed.
On the surface the indicators point to low system pressure (low refrigerant). No radiator fan, no compressor, no signs of life. However it's not the only possibility.
If you have a local garage, ask them if they have a set of air conditioning service gauges and if they will check the system pressure. ONLY CHECK THE PRESSURE!! Don't let them "fix" it yet! If the static pressure is "around" 90psi, the problem is NOT the refrigerant. The actual pressure that it should be will depend on the temperature of the day.
Loss of refrigerant, either quickly or slowly, without any external signs I.E. oil leaks, is not uncommon.

[xantia_v6]

Other issues: I have engine warning light as a result of a permanent fault code with energy accumulator that began after I couldn't start it in cold of 2022 and had to replace battery. Battery was replaced by RAC and is a Varta, appeared to be similar in spec to one removed, certainly hope so for what it cost. Had occasional warning with cylinder 1 not contributing as much, no significant roughness in idle etc but have to keep an eye on it.

The problem with the A/C is probably linked to one of the power train fault codes, with the engine ECU disabling the A/C compressor as a result. Live data from the engine ECU should confirm that.

[ben341]

The problem with the A/C is probably linked to one of the power train fault codes, with the engine ECU disabling the A/C compressor as a result. Live data from the engine ECU should confirm that.

Hi Xantia, makes sense. The reason why I didn't think about this is because the air con light illuminates normally. Some other research suggested the light would flash or something similar if the ECU etc knew about a fault that would stop it operating. Could be complete nonsense of course.