Peugeot 505 GTI series 2 aircon no go

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Wilko

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Tadpole
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Dec 3, 2020
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109
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Newcastle
Hi people, just bought this car and the aircon isn’t working. It has a “climate control” slider which either heats or cools the cabin. The compressor clutch is not engaging. I put volts on the disconnected lead to the compressor and the clutch is working and so the issue is elsewhere. I would think that a thermostat would be involved and a relay somewhere. Has someone had this issue with the series 2?
A table of relay locations and functions might be of help. The cooling fan is
operational. Any advice on this problem would be very much appreciated.
 
First up check if there is any refrigerant in the system.
Has it been retrofitted with R134A fittings? R134A 3-way pressure switch? I am making the assumption that the system originally ran on R12?
There is typicaly a bunch of interlocked relays connected to the compressor clutch but you'll need a circuit diagram to figure that mess out.
See if you can apply volts to the compressor while the engine is running. See if the system gets cold, or at least cool. If the system doesnt get cold then it's most likely that the refrigerant has leaked out.
 
I'm no expert on aircon, but I understand that there is often some sort of pressure sensor which cuts power to the compressor clutch if there is no refrigerant gas. You first need to work out if there is refrigerant in the system. If there is no gas, the compressor won't come on.
 
Excellent Con.

There are several ways to shrink these pdf files to within the AF limit should it come up again. Ghostscript, for example, can do it for terminal lovers. BUT...

The easiest, and GUI way is to open the source pdf file in Libre Office Draw, and immediately export it as pdf. The export dialogue that pops up lets you reduce jpg image quality and also reduce the dots per inch (on the first tab). I have got these two well under a MB without serious degradation.
 
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ozVTR said:
First up check if there is any refrigerant in the system.
Has it been retrofitted with R134A fittings? R134A 3-way pressure switch? I am making the assumption that the system originally ran on R12?
There is typicaly a bunch of interlocked relays connected to the compressor clutch but you'll need a circuit diagram to figure that mess out.
See if you can apply volts to the compressor while the engine is running. See if the system gets cold, or at least cool. If the system doesnt get cold then it's most likely that the refrigerant has leaked out.
Click to expand...
Thanks for your help much appreciated .
I did the volts thing with the engine running and saw some activity in the sightglass along with a few bubbles and so it probably needs more refrigerant - it did appear that it was cooling somewhat.
I’ll take it to the aircon guys and see what they think- they did confirm that there is a low gas cutout.
 
simca1100 said:
I'm no expert on aircon, but I understand that there is often some sort of pressure sensor which cuts power to the compressor clutch if there is no refrigerant gas. You first need to work out if there is refrigerant in the system. If there is no gas, the compressor won't come on.
Click to expand...
Thanks for your advice - I got the clutch engaged with the engine running and there is some refrigerant circulating but with a few bubbles so like you say a cutout has stopped the compressor from working due to a sensor cut out. I’m taking up to an aircon place to confirm.
 
seasink said:
Excellent Con.

There are several ways to shrink these pdf files to within the AF limit should it come up again. Ghostscript, for example, can do it for terminal lovers. BUT...

The easiest, and GUI way is to open the source pdf file in Libre Office Draw, and immediately export it as pdf. The export dialogue that pops up lets you reduce jpg image quality and also reduce the dots per inch (on the first tab). I have got these two well under a MB without serious degradation.
Click to expand...
thanks for the tip
 
Wow. the circuit diagram is simpler than I thought!
There is no over or under pressure switch. It may rely on a super heat plug in the receiver?
The main (A/C) switch is "1". It supplies power to the thermostat (109), which will be located on the evaporator in the cabin. From there the power goes to the compressor clutch (108), condenser fan relay (8A1), idle up valve (111) and radiator fan clutch (8)!
Does your radiator fan, condenser fan on the front of the car come on as well as the engine idle increase when you turn the A/C on? Any of those? If not, have you checked the fuse block?
Is C5 a fuse block? Where is the ignition key cut off?
It has a transistorized cabin heater fan...that's cool.
 
I took the car to a aircon place and yes it was low on gas but the compressor wasn’t engaging as “ECO” was selected which disables the aircon - didn’t realise it was selected - feel like a goose! The cooling fan is intermittent and wouldn’t run while they were looking at it - they seem to think the fan motor is packing it in as thumping it brings it to life momentarily. I hope this isn’t the case as it mightn’t be possible to change out without taking the engine out heaven forbid!
 
I don't think that circuit diagram is the right one.
No connection to an "ECO" mode.
According to the circuit diagram, the main radiator fan is driven from the fan belt. But engaged and dis-engaged by an electro clutch!
There is an electric fan for the condenser, but that's on the front of the car, in front of the radiator (according to that manual).
 
ozVTR said:
I don't think that circuit diagram is the right one.
No connection to an "ECO" mode.
According to the circuit diagram, the main radiator fan is driven from the fan belt. But engaged and dis-engaged by an electro clutch!
There is an electric fan for the condenser, but that's on the front of the car, in front of the radiator (according to that manual).
Click to expand...
Sorry if I have used the wrong terminology- the fan that is intermittent is the heater blower fan, so air isn’t being distributed within the car.
 
Just done my 205 fan, brushes are easy to adjust to fit and the fan permits this with removeable covers, it works better than new and draws 11 Amps running at 12V. I suggest yours could do with the same TLC, if banging it is required then it's getting near to the need for this. Not hard at all. The 306 fan also was redone but by now you need to bend the metal back to get to the brushes and springs, designed obsolescence.
 
The blower motor is definitely open circuit
( probably worn out brushes ) there are spring clips - 2 on top and one on the side nearest the left hand mudguard. I have manage to unclip these, but something else is preventing the withdrawal of the motor sideways out of the square section
air intake. Another clip somewhere underneath?
 
Found some more clips underneath and one where the fan housing connects to the forward ducting. Not the most enjoyable job using a mirror to find the clips and somehow undo them. After managing to finally get the fan out of the engine bay, the brushes were found with little meat left on them and the commutator quite dirty. I got some replacement brushes which weren’t exactly the same but should do the job.
Then spent all day today putting it back
In the car. The sound proofing / insulation surrounding the fan housing is not in good condition
and falling to bits, but at least the main part of the housing is covered.
The good news is that air is now being blown into the cabin and the speed control works. The temp control thermostat is also working , switching off the aircon with higher temps selected.
 
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