Aircon Low Pressure switch

[Mike Hingston]

Hi, i have recently had my Air con re gassed, and was told my compressor was not working  as it was almost out of gas when topped up. i was told it was more than likely that the low pressure switch had tripped and would need a new one fitted. Can anyone tell me where this is located,or is there one switch that covers both high and low pressure, and if such a switch can be changed without having to take out the gas that was filled. the car is a 2008 focus mk2 titanium 1.8 diesel Hatch Back.

[TomsFocus]

The AC pressure switch isn't a switch that can trip.  It's a simple switch that gets pushed in to make a circuit when enough pressure is present.  As it relies on gas pressure acting on it directly, you do need to remove the gas before removing the switch.  Fortunately the switch can be bypassed easily with a jumper wire or even an unbent paperclip to rule it out as at fault.

I'm fairly sure is right in front of the firewall at the back of the engine bay, near the low pressure port, on the Mk2 Focus.

 

[Mike Hingston]

Hi Tom

The AC Pressure switch by the bulkhead is on the high pressure side which can be changed without having to re gas. there is another switch at the front, in front of the expansion tank. i,m not sure if this is the low pressure switch or not,that switch looks like it needs the gas to be removed first. As i know nothing about Aircon i am reluctant to try it. 

I will take a picture and post it soon.

[Mike Hingston]

Hi,As promised here are two photos. The first one is what i think is the low pressure switch located at the front of the car on the narrow pipe (the low pressure side).

The second Picture is the AC pressure switch. this is near the bulkhead and is on the larger pipe (the high pressure side). The one in the first picture looks like it doesn't undo without removing the gas, where as the one in the second picture can be removed without removing the gas.

As far as i can see there are no other switches on the AC pipes.

[TomsFocus]

The narrow pipe is the high pressure side.  Think of it like putting your thumb over a garden hose.

[Dan62]

The low pressure switch is on the high pressure side of the system. It indicates low pressure. It is your 2nd pic, Brown connector with 2 wires.

The high pressure switch is on the low pressure side of the system. It indicates high pressure. It is the first pic, Black connector with 4 wires.

If you suspect the low pressure switch, bridge the 2 wires of the connector to verify.
 

[Mike Hingston]

OK, I have jumped the two wires on the switch. Unfortunately there is not any power at the switch, so I'm going to have to back trace the wiring to find the fault. Not something I'm looking forward to, especially not without a wiring diagram.

[iantt]

1 hour ago, Mike Hingston said:

OK, I have jumped the two wires on the switch. Unfortunately there is not any power at the switch, so I'm going to have to back trace the wiring to find the fault. Not something I'm looking forward to, especially not without a wiring diagram.

Now you got no answer excuse😂😂😂

[Mike Hingston]

Thank you, But unfortunately this image is blurred and i can't understand the writing or see what colour coding the wires are, I have been looking on the internet for weeks trying to find a decent wiring diagram. very much appreciated.If you can send my a link to the page that would be very helpful.

[TomsFocus]

5 minutes ago, Mike Hingston said:

Thank you, But unfortunately this image is blurred and i can't understand the writing or see what colour coding the wires are, I have been looking on the internet for weeks trying to find a decent wiring diagram. very much appreciated.If you can send my a link to the page that would be very helpful.

Images are automatically compressed by the forum.  If you click on it, it will open the high resolution version.

 

[iantt]

2 hours ago, TomsFocus said:

Images are automatically compressed by the forum.  If you click on it, it will open the high resolution version.

 

I did wonder why he couldn't see it as I could by clicking on it ok. I checked first before leaving the post. 

[TomsFocus]

20 minutes ago, iantt said:

I did wonder why he couldn't see it as I could by clicking on it ok. I checked first before leaving the post. 

It is a bit annoying, as it makes any new car photo look like it was taken in the 80's and makes anything with writing unreadable.  

I suppose it's useful for anyone still on 56k dial up modem though.

 

[Mike Hingston]

got it thank you, and I'm not on 56K dial up lol

[iantt]

1 minute ago, Mike Hingston said:

got it thank you, and I'm not on 56K dial up lol

Carrier pigeon? 

[Mike Hingston]

Ok , i brought a tester to check weather or not i had a connection. looks like electrical system is Ok , So looks to me that the switch is faulty.My question is can the switch be removed without draining the system, i think it can. I have seen a video on you tube, but not totally convinced. What do you think.