Climate Control Fan Won't Stop

[Damien]

Okay, here's the deal:

2000 AUII Fairmont

I got home from shopping (which is only 2 minutes up the road) and turned the car off and the fan continues to run even without the keys in the ignition. I've tried disconnecting the battery, pulling fuses the whole bit. Called the NRMA and the guy disconnected the fan using the plug behind the glove box so that I could at least drive it without having to keep disconnecting the battery. He said he'd heard of this before and thought it was something to do with the actual climate control panel, I seem to suspect it's a dodgy relay.

Any thoughts? Anybody ever experienced this before?

[Perana]

I know it may be different but my EA did exactly the same thing. It ended up being the fan speed controller which is a silver box mounted in the heater box area.. Im not sure exactly where it is on the AU's but you should be able to find it by tracing the fan wiring back.

[The Dok]

Try this, should at least tell you what (if) there are any problems. (Simple procedure, ignition on (engine not running) press the 2 buttons at each end of the "climate control unit" (off & face/floor) at the same time, the unit will go into a "self diagnostic mode" effectively re-setting itself). Have had drama's with mine in the past, there are also many threads about them, try a search if the diagnostic mode doesn't fix it. _2:

[XRQTR]

If you can't find it best thing is to go to your local Ford sevice department and get them to diag the problem, make sure to tell them that you only want a diag and will approve the work after you know the costs involved so they don't just go ahead and fix it and hit you with a bill.

When they give you an answer you have two options, if it's cheap enough get them to fix it or if not then get your regular mechanic to do it for you if you can't do it yourself.

[Damien]

Thanks guys,

I'm about to go and try the Diag Mode and see how that goes. I only bought the car about 5 months ago with a 5 year extended warranty, but I doubt the electronics of the AC would be covered under that warranty. If I can't sort it out myself I'll pop it in to the dealership I bought it from and get them to tell me what's wrong, but NOT to fix it without my approval.

Cheers again guys, if anyone has any more suggestions or links to previous threads it is all very much appreciated. I'll be doing a search later to see what I can find.

[aussiblue]

The main transistor in the fan speed controller that sits in the a/c air intake duct to keep cool will have corroded and shorted. Leaves and moisture get caught in the duct sit on the transistor casing and rust it away. Replacement transistor can be had from Worldwide Electronics http://members.iinet.net.au/~worcom/ for less than $15.

[smally289]

Yep, as above. Have seen this a few times and it was always the fan speed controller.

[Damien]

Okay, so I'm either looking at a new Fan Speed Controller or just replacing the transistor in the current Fan Speed Controller, right? *sigh* Either way I'm pulling the dashboard apart, aren't I? Or I'm taking it to Ford or an Auto Electrician and they're gonna say "New Fan Speed Controller, plus labour = some crazy amount of money" for something I could probably do myself in a day.
Alright, so I'm prepared to do this myself, but I don't fancy pulling the dash out twice (once to work out which transistor I need so I can order it and once to replace that sucker) so I'm gonna put my plight to you guys. Anybody know the specifics of this transistor so I could order it without having to pull the dash apart to find it? Furthermore, what would you do? Bear in mind that I've never tackled anything involving airbags before and I assume (unless somebody can tell me otherwise) that to get to the FSC I'll need to take that out, right?

Everybody's guidance and information is greatly appreciated.

Cheers...

[smally289]

Dash doesnt have to come out, just the glovebox. You could fit it in 10 mins with your eyes shut!!

[aussiblue]

Yes no dismantling of dash is required; it's the silver box on the firewall and you even remove it without lifting out the glove box - if you were a contortionist. Transistor is Motorola 2N5686 The box opens easily by bending the tabs and its not too hard to unsolder the transistor and replace it - just ensure the orientation is correct so you don't reverse wire it.
To prevent the transistor failing again I suggest you add a TO-3 plastic cover (Cat ZM-0004 at Jaycar, Cat H7290 at Altronics, **** Smith have them but I can't find it in the catalogue) and /or an additional TO-3 heatsink (part number H3400 at Disk Smith, Cat number H0610 at Altronics, and HH8510 at Jaycar). These will keep the leaves away. You can also spray the transistor's outer case with circuit board lacquer or something similar for added protection.

[Damien]

Thank you, thank you, thank you!!!

That is the best news I've heard since this thing broke, you guys are awesome.

Alright, gonna order those parts today and get this thing working. Poetic justice, the hot weather kicks in and the AC breaks, LOL

Cheers guys, I really appreciate this information, you have probably saved me a LOT of $$$

[Damien]

Well the transistor turned up on Monday afternoon and I got a chance on Tuesday afternoon to pull the Fan Speed Controller out and tackle this problem. Sure enough, I pulled the FSC out and the transistor was badly corroded. I got the vacuum in there and sucked out some stupid amount of leaves. Moral of the story? Clean the leaves away from the AC intake! This is something I'll be doing on a regular basis.

Anyway, I installed the new transistor and tried to get the heatsink from Jaycar to fit as well but there wasn't enough room because the case of the transistor sits between the FSC case's own heatsink fins which then sit inside the AC intake. On another note, both Jaycar and Altronics reported that TO3 transistor covers are now an obsolete model so I wasn't able to obtain one (not that I tried very hard mind you) so instead I sprayed two coats of PCB Lacquer onto the exposed case of the transistor. Hopefully I won't have this problem again, although I bought a spare transistor just in case.

Once the FSC was refitted with the new transistor it was the moment of truth, I reconnected the AC fan and all the other connectors, reconnected the battery...no fan noise (so far so good), started the engine, turned on the climate control...it worked, first time. More importantly, turn the engine off and the fan switches off just like it's supposed to. You couldn't wipe the smile off of my face with a baseball bat.

Attention anybody who owns a Fairmont or other variant with Climate Control, take note of the part numbers listed above. This advice saved me at least $300 and is a very easy thing to fix by yourself, but seems like it could be quite a common problem, especially if you have a lot of trees around your car on a daily basis (like me). Thanks to aussiblue and smally351 for their very specific information and advice, most appreciated. Thanks to the other guys who responded and Mike from Worldwide Electronics, your help was very much appreciated.

Cheers guys,

Damien (now fresh and cool once again)

[Dezza]

Edit: My question's been answered.

[aussiblue]

Jaycar to fit as well but there wasn't enough room because the case of the transistor sits between the FSC case's own heatsink fins which then sit inside the AC intake

It takes some maneuvering but it will fit.