Air Con Fault, Electrical burning smell

[XM_on_ a_ shoestring]

I was in my car returning home on Saturday evening when an acrid smell (motor windings burning type of smell). At first I thought it was from outside, (I was near Chapel en le Frith and thought it was probably the Ferodo factory!). Anyway it continued smelling all the way home. The smell seemed to be coming from the dash area. The fan just made it worse.
The next day I went out and tested it. I turned off the air con - the smell went. I turned the air con on the smell returned. So it must be some solenoid or relay that operates the air con. Any ideas where to start on this?

[noz]

Hi shoestring,

Have you tried turning the fan on without the air-conditioning? I've a fancy its the fan motor windings or the thyristor pack on the fan housing used for speed control. The fan motor and the thyristor pack are both in the airstream.

The only component of the 'Air-Conditioning' equipment in the airstream is the cooling coil and the smell's not coming from that. All other AC kit is under the bonnet out of the airstream where you've only a very small chance of smelling it.

If it turns out to be the fan there's a fix-it file in the "Self Help Files" section.

Please let us know if you've carried out any more tests.

Cheers

noz

[XM_on_ a_ shoestring]

Hi Noz
I've had the fan running without the air con on and the smell disappears. The fan operates at all speeds with no problem in auto or manual.

[noz]

Hi shoestring,

OK we'll try the next possibility. The intake for the fan is below the scuttle panel at the bottom of the windscreen. There may be some electrics associated with the AC in this vicinity so that when it starts cooking the smell is drawn in by the fan and distributed inside the cabin. Of course this presumes the burning smell is coming out of the vents. Is it? Or is it coming from somewhere else? Theres a bunch of electrics down in the driver's footwell just above your feet. There's also some electrics above the passenger's feet. Can you be more specific on the location of the smell?

Cheers

noz

[XM_on_ a_ shoestring]

Hi Noz
The smell does appear to be coming out of the vents when air con is switched on. I'll have a check on Saturday as I 've got a bit of time. Will I need to take the glovebox out to make it easier to inspect all the electrics or do I have to access from passenger footwell to get to the suspect area.
Regards
xm_on_a_shoestring

[noz]

Hi shoestring,

All the fan components are accessed from below. There's a modesty panel above the passengers feet which you remove first. All the components are then accessible.
The flap motor which drives the air direction flap is located high on the passenger side and can be helped by removing the glove box. However, I'd suggest checking the easy things first.

Cheers

noz

[jorgy9]

Hi there,

something similar has happened to me but only once. Some evening, just after leaving a friends place, the fan brought an intense burnt smell in the car. I immediately pulled aside and switched off the engine. I restarted after a minute and it was fine. Never happened again. Only, in the following month, I got 2 or 3 times the electronic climate control sticking, ie buttons were not responding. Only solution to this was to switch off and restart. Nothing else happened since. My Indy said it could have been leaves in the fan having caused a shortcut.

George

[XM_on_ a_ shoestring]

Hi Noz & All
The smell seems to be from the fan area. I've removed the panel in the passenger footwell to access the motor. Do I need to remove the motor to get to the air con electrics you mentioned?
Now, another weird thing happened - unless it's normal. When I engage the air con the two radiator fans kick in as well, is this normal? It's the first time I've noticed this whilst I've had the car(2.5td estate).
Regards
shoestring

[Craigdp]

yes that is normal

[Pac]

Hi XM_on_ a_ shoestring

If your heater control panel is the one that's got "buttons" only it might be worth your while to take the control panel off and have a look at the right side of it for signs of overheating as in melted plastic cover. Mine is overheating there when I run the fan without the a.c. The fan and the a.c both work ok but temp control seems now to have 2 settings, hot when its set to 30degrees and cold at any other setting.............. except when the a.c is on when everything seems ok. Weird or what?

[XM_on_ a_ shoestring]

Hi Pac
Yes the heating system is weird. I managed to get to the fan itself checked around there for anything unusual. All seemed fine. I cleaned the fan out blew out the motor with compressed air hose. Reassembled.
I then put ac on and have managed to locate that the smell is coming out from the dash area where the buttons are for heater controls, the side vents do not smell but the centre two do. Also the smell does seem more of a plastic smell than "electric windings" type smell.
So yes I'll have to remove the front dash to see what's the cause.

Thanks
shoestring

[XM_on_ a_ shoestring]

I've attached a page with some piccies on of the heater switch control (button type).
As you can see it has GOT A BIT HOT!! I took the panel down to my local electricians for a check over expecting the resistor(green one) to be shot it. He rang back to say there was nothing wrong , so I could go and collect it.
While it was in for check over, I noticed that one of the three relays had overheated and melted around one of the contacts. I'll post that as soon as I've took a piccie.
The relay that had melted still works!
I went to collect the heater panel (he did the check for free), he only chearges if any components need replacing.
He came up with some interesting possibilities. He said the probable cause was a short circuit, or it could be a sticking solenoid that kicks in to operate the air conditioning maybe somewhere round the pullies, he obviously doesn't know where the solenoids is.
If it's sticking that could be causing the overheating.
So, if there is a solenoid that operates the air con, where do I locate it and is it serviceable/accessable?
shoestring

[XM_on_ a_ shoestring]

The piccies didn't load up so I've tried again.

[XM_on_ a_ shoestring]

Hi again,
I just wanted to add that when I refitted the heater panel, the smell has gone(for now) and it works with air con on or off!! How weird is that?
Maybe he has a point about a sticking solenoid?
shoestring

[XM_on_ a_ shoestring]

I had my air con regassed last Friday(22/07/06). It was low on gas. Apparently the system will shut down and not operate when it gets down to a certain level of gas left in air con system.
My local xm garage repair man says the air con systems can lose between 20-30%, and therefore can become onoperable between 3-5 years.
Now he's regassed it, it works ... now and again. The AC light on dash switches on and off.
The electric smell is appearing while the AC is on. When I turn off AC, the smell goes again.
I looked under the bonnet. The nearside relay has the bottom terminal(no. 5) melted ...can this be related to the circuit board AC control panel behind the dash that has been making the smell when it gets hot?
I've attached a jpeg of the culprit relay.
Where can I get one of these. It's a Cartier 12v/25a.03.501.
Do Lucas do anything similar or perhaps fit one with a higher amperage, or would that just hide the problem? Is the 25a up to the job?