Aircon keeps turning on and off

Post your Cit/Peu/Ren air conditioning queries or advice.

Moderator: RichardW

User avatar
Posts: 700
Joined: 23 Nov 2002, 20:15
Location: Bolton, England
My Cars:

Aircon keeps turning on and off

Post by wrinklet1 » 16 Sep 2007, 19:37

My aircon has been playing up. The 'clutch' has been clicking on and off when i turn the aircon on. I have chacked and it all seems ok. Now, I have looked at so many posts about xantia aircon, and have connected two wires that go to the aircon pump together. The pump now switches on and off as needed with the switch on the dash and the cooling fans come on.
So, I reckon that the 'relay/switch' on the dryer? with the eye hole has knackered. Am I right and what i have done is it ok?

Hope this reads ok

1xAmi,3xGS,2xBx,2xAX,2xSaxo,1xXantia mk I,2xXantia MkII,1xC1,2xC2,

User avatar
Posts: 4273
Joined: 11 Jun 2007, 16:17
Location: Christchurch, Dorset. UK
My Cars: 2005 C5restyle 1.6HDI 16v 110hp VTR Estate
x 120

Post by MikeT » 16 Sep 2007, 19:57

It's normal for the aircon to switch itself off as needed. It also has a safety feature that stops it operating with insufficient pressure/gas.

Other than that, I don't have a clue, sorry.
98 S2 Xantia Hatch 1.9TD 143K
CX 2400 GTi

alan s
RIP 2010
Posts: 2542
Joined: 26 Jan 2001, 16:53
Location: Australia
My Cars:
x 4

Post by alan s » 16 Sep 2007, 22:29

If it runs for a while and then drops out, then cuts back in, that could simply be it cycling on the thermostat which is what it's supposed to do to maintain the pre set temperature.
If it clicks in and out every few seconds, then it could be something a bit more sinister. This could be as you suggest, the HP/LP safety switch atop the receiver dryer, a dodgy connection/dry joint, a faulty sensor or another one that gets under the radar at times and that is the fans at the front of the radiator. They should both operate when the air/con is on, but as can happen, one can fail intermittently due often to worn carbon brushes. In this case, the remaining fan can switch to high speed and cycle in fairly quick succession as it battles to reduce the head pressure.
I'd be firstly checking the sight glass on the receiver dryer for signs of bubbles, a sign of low gas and also check the condensor for excessive heat, a sign of high head pressure. If either of these symptoms are present, reconnect the control ASAP and get it checked out and rectified before you have a disaster.
By passing that control for any more than a couple of seconds for testing purposes is a bit brave IMO as I have had gauges on faulty systems that have registered 450 psi as a maximum reading, and had them hit the stops passed that, so with the safety switch bridged out, there is a real reason they can cause some serious damage if they decide to blow.

Alan S
RIP Sept 19th 2008.

She said "Put the cat out" She didn't mention it was on fire!!

Posts: 159
Joined: 03 Mar 2006, 23:20
Location: Near Poitiers, FRANCE
My Cars:

A/C problem????????

Post by fridgedoc » 25 Sep 2007, 17:16

Hi Paul

I would take notice of Alan's advice 100%

I work on A/C systems on many makes of vehicle

As Alan states shorting out safety high pressure switches is a BIG NO NO !!!

only do this for a few seconds otherwise you could cause major damage to the A/C system and more importantly YOURSELF.
Bonne Chance


LHD Xantia 1994 (deceased)
LHD Xantia 1995 Berline