Problem with wiring to Compressor

Unread post by **KennyW** » 05 Jun 2006, 20:58

Hi Gang,

Have got the A/C sort but it would appear to be a electrical fault some where from the connector at the compressor to elsewhere in the system.

I've got a person recommended by several garages and others in the know in Edinburgh looking at the problem.

He states the system is up and running and the compressor is definitely working because he disconnected the wiring loom from the compressor and bypassed same.
This resulted in compressor and the clutch working correctly and when he reconnected it to wiring loom it stopped working.
Any suggestions

JohnM52 · Unread post by **JohnM52** » 05 Jun 2006, 21:16

Hi KennyW

Have you tried connecting 12volts from the battery to the input side of the connector to the trinary switch. In simple terms (just in case the language is strange) the connector which goes onto the big screw in sensor on the drier unit ( probably in the area of the right hand wing near the control boxes - opposite side to the battery - has four wires to this. Two are fairly heavy guage, and two are quite fine. The first of the heavy guage ones feeds the remainder of the circuit including the compressor. If you apply 12v into that lead, from the battery, the compressor should kick in. If it does, come back and let us suggest the next move.

I have just gone through a long exercise of tracing circuits to find a similar fault on my XM so I might be able to help but it is one step at a time.

I am presuming that evertyhing else in the system is OK of course.

I am in Edinburgh, who are you using?

Unread post by **KennyW** » 05 Jun 2006, 21:30

Hi John,

I,m using Steve Yorkston of tradetech,ClockMill lane recommended by a few garage pals and a few autotrade suppliers.

Kenny

P.S. I'll be speaking to him tomorrow anyway

Clogzz · Unread post by **Clogzz** » 06 Jun 2006, 13:03

There’s also the interior blower fan that’s got to spin before the air conditioning can work:

http://www.frenchcarforum.co.uk/forum/v ... hp?t=19108

Unread post by **KennyW** » 06 Jun 2006, 19:36

Thanks John and Clogzz,

Spoke to my friendly A/C man and he since found out the clutch on the compresor is not working

I've still got the original

so I would like to know if there is any means to check if this clutch is working correctly.

I can get a hold of another compressor but I don't want to go through unecessary work if possible

Any suggestions greatly accepted.

If anyone is wondering why you should have been walking in Edinburgh today temp 25 C !

Clogzz · Unread post by **Clogzz** » 07 Jun 2006, 13:50

Hi Kenny,

From your description of the aircon man applying voltage to the clutch, causing it to kick in, would mean that the clutch is working.
If not, you may be able to part the clutch from the original compressor, and swap it for the present one.
To test the original one, apply 12 Volts to the terminals, and it should click on loudly.
Careful not to get fingers caught when it engages.

Nice to read about the warm weather in Edinburgh.

It’s a bit cooler than that here these days, but there’s still always a harsh bite in the sun.

Regards,
Terry.

Unread post by **KennyW** » 07 Jun 2006, 17:37

HiTerry,

Same again today as a member of her majesty's constabulary and required to walk in this weather it's abit much

Re the clutch there is an update

It's knackered but on both i've got but i found another which looks good and is clicking when 12v is passed.

Ichecked the offical citroen part site and a new clutch is £302

A compressor is only

£50 notes more

Will let you if all turns out well.

P.S.

Have you dismantled the clutch mechanism before

Once working I'm going to do this to the knackered ones

Clogzz · Unread post by **Clogzz** » 08 Jun 2006, 14:43

Hi Kenny,

Never dismantled the compressor clutch, so can’t be any use for that.
First would be to check the continuity of the wires.
With a bit of luck, only the coil would be open, and the mechanical part would still be good.
There should be a way to check the mechanism for free movement.

Her majesty’s constabulary should be spared any unnecessary trudging along city streets in the heat.

In summer, it’s 30ºC every day for over 3 months here.
That’s measured at the nearby airport, in the shade, on the grassy patch, and in the sea breeze.
Walking on pavements along walls, it’s quite a bit hotter.

During the middle of the day, everyone goes under cover.

Best wishes,
Terry.

Unread post by **KennyW** » 08 Jun 2006, 16:58

Thanks Clogzz for your kind concern

and also the info re clutch.

Will get back to forum with a result but unable to check until next week.

Cheers

Kenny

Unread post by **alan s** » 09 Jun 2006, 00:25

Here you go Kenny, this might make life a bit easier for you.

http://www.sanden.com/support/pdf/sd7servicemanual.pdf

Alan S

Unread post by **KennyW** » 09 Jun 2006, 20:50

Thanks Alan for the reply , but my compressor is a delphi harrison and their site does not have a manual.

Thanks anyway,

Kenny

AndersDK · Unread post by **AndersDK** » 09 Jun 2006, 21:03

Its the clutch at problem you have found out ?

To my knowledge this is a fairly common type electromagnetic clutch - as used on some mechanical cooling fans also.
These have a slip ring and sliding brush for +12V power transfer into the rotating magnetic coil. Sometimes they also have a brush & slipring for the chassis earth transfer.

Brushes worns out and slip rings gets burned or corrodes - meaning the electromagnet does not get necessary power to engage. I would like you to check this simple solution before forking out for a new clutch - possibly saving you a bag of money.

Unread post by **KennyW** » 11 Jun 2006, 20:50

Thanks for the reply Anders,

I've been lucky to find another second hand compressor which is very clean looking and when 12V's are passed to the clutch clicking can be heard so I'm hopeful this will work.
Will get the other ones and remove clutch to check bushes etc and i will get back to the site with necessary info and even some pics.

Cheers,
Kenny

Unread post by **KennyW** » 15 Jun 2006, 17:17

Hi Gang,

Had car back at Air Con man and he has re checked his work and it appears to be a wiring fault somewhere.
He has been in touch with a company who has the wiring diagrams etc for technicans.
He has checked the various elements on the circuits ,pressure switches,relays , fuses etc and he bypassed the wiring for both fans and they worked.He bypassed the wiring for the compressor and it worked.
He followed the wiring back to fuse and relay in engine compartment and it was okay.
He gave up before he got too frustrated and is looking for any opinions.
I'm going to contact a good auto spark I know.

Any suggestions would be gratefully received.

Compressor type Delphi sames as on peogeot 405/406 and early C5's.

Clogzz · Unread post by **Clogzz** » 16 Jun 2006, 15:25

he bypassed the wiring for both fans and they worked

Does that mean that the fans weren’t working when the air conditioning was switched on ?
The sequence is that the engine must run first, then the interior fan must spin next, then the dashboard aircon switch must be on, and lastly, the two cooling fans must start at the low speed.
If it doesn’t get that far, then the fault is in the above sequence, and the system hasn’t got to the pressure switch and compressor yet to find out what state they’re in.
I have experimented by unplugging the pressure switch, and that silently released the clutch, but the fans kept spinning.
Plugging it back in caused the clutch to click on loudly.
I’ve got a post on the subject, and will edit it in, if I can dig it back up.
Finding why the fans aren’t spinning may be enough to fix the lot.
The common cooling fan fault won’t prevent the compressor from starting, but if the sequence doesn’t go as far as the fans, it won’t go any further either.