Board logo

Any air con experts out there?
speedyxjs - 12/12/10 at 05:09 PM

Ok, im expecting this one to be an easy one that will make me look like a complete numpty but at the moment i cant figure it out.

I had a quiet day at work on thursday so thought inbetweent he jobs i did have, id work out why the air con compressor on my car was always on. Turns out that one of the previous owners had bypassed the air con clutch relay by cutting and twisting some wires together and covering in inulation tape (i was not impressed!).

Anywho, after removing the bodge and tidying up the wiring, i am now left with non working air con (ie the clutch wont operate when switched on). I have tried 3 other relays just in case, a spare air con switch i had and the fuse. After some research, i have also found out that the radiator fan shouldn't be on all the time but works with the air con which is also strange as the air con now isn't on but the fan is.

I have posted this on a jag forum but not had any replies.


steve m - 12/12/10 at 05:16 PM

So if you redoo the bodge, will it work ?


speedyxjs - 12/12/10 at 05:22 PM

Yeah but id like to be able to switch it on and off without undoing the bonnet and pulling out a load of wires


Richard Quinn - 12/12/10 at 05:40 PM

quote:
Originally posted by speedyxjs
Yeah but id like to be able to switch it on and off without undoing the bonnet and pulling out a load of wires

Extend the wires and poke them through the dash? That way you can twist and untwist them from the comfort of your seat


steve m - 12/12/10 at 05:42 PM

Yep, have to agree !!


Stuart_B - 12/12/10 at 06:15 PM

or extended the wires, and fit a switch, or put them on to the existing air con switch?

sorry not much help with that, but could the clutch be at fault?

stuart


rusty nuts - 12/12/10 at 06:19 PM

Is the pressure switch working and switching the relay? If the gas pressure is low then the switch will not work. Must sort mine out before the summer!


Peteff - 12/12/10 at 06:29 PM

If the aircon won't switch on it's usually because there is not enough fluid in the system to pressure it. It will seize the pump eventually running it all the time with not enough fluid. Get the system filled and undo the bodge then try it for proper operation.

[Edited on 12/12/10 by Peteff]


jonesier1 - 12/12/10 at 06:32 PM

when it works ie the clutch is operated is it cold ? if not the gas could be too low or the pressure switches are not operating which by the sounds of it could be down to the fan.Get the fan working as it should first.


speedyxjs - 12/12/10 at 06:54 PM

The system has just been regassed and the pipes get very cold with the bodgein place. I was told the pressure switch is what switches the fan on (overides the temperature switch in the radiator). The reason i am trying to sort it now is because on my way to work, the engine isn't reaching normal operating temperature due to the fan working overtime. This hasn't been a problem in the last 4 years as i havn't used it as a main car until this year.

[Edited on 12-12-10 by speedyxjs]


Peteff - 12/12/10 at 08:45 PM

The fan on the air conditioning condenser should not affect the fan on your engine radiator, which fan is it that is running all the time? Your air conditioning fan will cool the condenser but not your engine, is the clutch on the air conditioning compressor kicking in all the time or is the compressor freewheeling as it should when the air is switched off. You should hear it clunk when the magnetic clutch kicks in and the engine revs will probably drop. Does your engine radiator have an electric or viscous fan as you could remove or disconnect it in the present weather quite safely. Air and engine are two different systems with no connection usually.


speedyxjs - 12/12/10 at 09:16 PM

quote:
Originally posted by Peteff
The fan on the air conditioning condenser should not affect the fan on your engine radiator, which fan is it that is running all the time? Your air conditioning fan will cool the condenser but not your engine, is the clutch on the air conditioning compressor kicking in all the time or is the compressor freewheeling as it should when the air is switched off. You should hear it clunk when the magnetic clutch kicks in and the engine revs will probably drop. Does your engine radiator have an electric or viscous fan as you could remove or disconnect it in the present weather quite safely. Air and engine are two different systems with no connection usually.


It only has one fan for the radiator and condensor. That is why when the air con is usually switched on, the fan switches on. Witht he system wired properly (as it is now) the clutch doesn't work at all whether it is switched on or off. If i redo the bodge, the clutch is perminantly on whether it is switched on or off in the car.


Peteff - 12/12/10 at 09:24 PM

I would wire a switch to the magnetic clutch and another to the fan so you can work them independent of each other. I know it sounds like another bodge but it's probably how it should work anyway. The compressor should work only when your heater fan is on as well so if you can work a relay in from the power to that you should have something like the original system.


paulf - 12/12/10 at 10:07 PM

The rad fan will usually cut in if the pressure switch in the air con system detects to high a pressure , it may also cut out the compressor clutch so if you have had it refilled recently I would check the amount of gas in the system and also was it properly evacuated with a vacuum pump to remove all of the air before re gassing?
Paul


Mark G - 12/12/10 at 10:24 PM

It must have been bodged up for a reason, I'm going to make an educated guess and agree with a comment above that the pressure switch is probably shot. The A/C compressor won't activate if there isn't enough gas/pressure in the system because the gas has lubricating properties and without it your pump could be damaged.

I'd be tempted to look at the wiring to the pressure switch and see if it switches when the A/C builds up pressure.

Personally I'd rather fix one bodge properly over making a few slightly more elaborate bodges.


speedyxjs - 13/12/10 at 07:45 AM

quote:
Originally posted by Mark G
It must have been bodged up for a reason, I'm going to make an educated guess and agree with a comment above that the pressure switch is probably shot. The A/C compressor won't activate if there isn't enough gas/pressure in the system because the gas has lubricating properties and without it your pump could be damaged.

I'd be tempted to look at the wiring to the pressure switch and see if it switches when the A/C builds up pressure.

Personally I'd rather fix one bodge properly over making a few slightly more elaborate bodges.


Me too. Il look at the pressure switch sometime this week. Thanks for the help guys