Air con electrical problem

[16vMK2 to 172Sport]

Hi,

Just been to get my air con regassed at a local garage as the a/c pump didnt appear to switch on when you hit the a/c button. It turns out that the a/c system was fine and reasonably air tight. The problem is something electrical! :dead: The pump it self is fine as they managed to force it to turn on by doing something with the relays, they suggested it could be a pressure switch or even just a broken wire somewhere.

What im wondering is, should I take it to a garage to fix or try doing it myself? If it's a common fault then I would just do it myself. Has anyone had the same problem?

Any help much appreciated! Cheers

 

[Jay Payne]

If you bridge the pressure switch and the compressor clutch clicks then its either the pressure switch faulty or low gas level.

The pressure switch stops the relay activating the clutch if the pressure is low (so you dont shag the compressor)

Make sure you have a feed at the relay from the dash switch

 

[16vMK2 to 172Sport]

Well the garage regassed it so it's not that. I can't remember what he said he bridged to force it to kick in (i thought it was a relay or something), perhaps it was the pressure switch he bridged?

Where is this pressure switch we're talking about? Is there only the one switch it can be? Any ideas on cost of a replacement?

Cheers

 

[Jay Payne]

If its the pressure switch it will need vac and regass to change it

 

[16vMK2 to 172Sport]

doh!!! not really a DIY job then is it...

 

[Jay Payne]

Surpsprised the garage didnt sort it for you.

But I guess they charged you for a re-gas anyway? Di they say how much gas the recovered from it in the first place?

 

[16vMK2 to 172Sport]

yeh they just charged for a normal air con service, £35 - they removed about 600g of gas, held it under vacuum for 15 mins, then added about 700g of gas, so nowt much wrong with the pressure system.

He said if I wanted them so sort it I would have to book it in with them again, he reckoned he needed it for another hour, or more, saying it could be anything.....:S

I want to go about this in the cheapest possible way (spent a small fortune on my car this year so far!!). What do you suggest? Perhaps ordering the pressure switch myself and see if they will fit it and recharge the system for another £35?

 

[16vMK2 to 172Sport]

If its the pressure switch it will need vac and regass to change it

i don't suppose there is anyway to get arround this is there?

 

[16vMK2 to 172Sport]

Can anyone tell me where this pressure switch is located and how I can test if it is that which is the fault?

Also, anyone know how much they are to replace?

 

[Jay Payne]

Im not sure where the pressure switch is but should be easy to spot. Will be in one of the pipes cant remember what side of the system now, its been quite a few years since i worked on A/C.

You can bridge the switch and the A/C compressor should work then.


look at all the pipes and find one with an electrical conection,

 

[Paul RN]

If you find it let me know

 

[Paul RN]

I've looked and I can't see any wiring attached to the air con pipes. Hmmm.

 

[Jay Payne]

Any in the condensor?

 

[Paul RN]

Looks like it will take some work to have a look there

Its almost laughable the workshop manual mentions the torque for it but not where the switch is. My air-con is intermittent, its been re-gassed with no leaks. So I'm assuming its either the relay (which sounds when you press the AC button) or the pressure switch.

 

[Alexjfinch]

This was what was wrong with mine.

Pressure switch is screwed into the condensor behind the grill somewhere - can't remember which side it is.

It can be removed and fitted without a regas (did mine without a regas, there is a Schrader Valve behind it) and it has a 3 pin plug plugged into it.

I think it was about £35 from Renault

 

[Jay Payne]

^there you go, simples

 

[16vMK2 to 172Sport]

This was what was wrong with mine.

Pressure switch is screwed into the condensor behind the grill somewhere - can't remember which side it is.

It can be removed and fitted without a regas (did mine without a regas, there is a Schrader Valve behind it) and it has a 3 pin plug plugged into it.

I think it was about £35 from Renault

Thanks for the info mate! If you can change it without a regas then thats very pleasing news! Did you do it yourself? Easy job / time consuming?

May seem a silly question, but what is the best way to go about 'bridging' the switch to test if it is at fault? I have no idea how accessible it is or what kind of connection it is...

 

[Rob]

Interested to know this also, I'll try a regas first, but if that doesn't work, at least I'll have some idea where to go with it.

 

[Paul RN]

Its on the right hand side. If you look at the front right hand side next to the bonnet switch, peer over into the engine bay underneath roughly where the bonnet switch, you can just see the 3 wires going into the back of the sensor.

Ended up taking out the airbox to get a better angle on it. Cleaned mine up first of all to see how I get on.

 

[16vMK2 to 172Sport]

I think it was about £35 from Renault

You having a laugh?!?!! Renault just quoted me £101 inc. vat for it! How on earth can they charge over £100 for a bloody switch!?!? Renault = jokes!

Luckily ECP can get one for £40ish

 

[16vMK2 to 172Sport]

Just been thinking, when I had it regased the guy forced the aircon to kick in by bridging the relay, not the pressure switch. Would this mean the relay is at fault and not the switch?

 

[Alexjfinch]

I got one out of Renault for £40 I swear.


You can't bridge it because its 3 pin so you can't short it out.

 

[16vMK2 to 172Sport]

Just been thinking, when I had it regased the guy forced the aircon to kick in by bridging the relay, not the pressure switch. Would this mean the relay is at fault and not the switch?

Can anyone answer the above question?

 

[Jay Payne]

A: Not nessisarily. If a relay is bridged all it proves is that the circuit from the main use to the compressor is working. It doesnt test the relay or the switch

 

[16vMK2 to 172Sport]

well £170 later I finally have air con! Its a welcome relief with the recent weather we've had. Ended up just taking it to an autoelectrician to diagnose and repair - £60 labour £110 for the switch!:dead: