Winter is a coming...therefore heating must fail. C5 Mk I

[frenchcarnut]

Well, it's that Law again known to Mr Sod and his entourage of spellbinders and talismen. The one that comes in just when you don't need it - a week before a holiday, with much to do and no time to do it..........stating as a text from Mrs Frenchcarnut which goes, "The heating's not working"

"Do you mean the blower or what is not working?" went back my clarification request...but alas no response from the source, only silence that will no doubt be punctuated later in the day when the car returns to the doorstep!!!

Well, I will wait and see before jumping in with both feet to assume another few hundred notes at least, but I've yet to confirm it's the blower or the fact that no heated liquid is circulating through <sigh>.

Are there any known heating issues on the C5 Mk I to get me started?

Cheers in advance

[Clogzz]

The coolant always flows through the matrix, with nothing to regulate or stop it.
The blower module transistor IRFP064N is in the habit of packing up, somehow just like on the Xantia.
The module can also be replaced, but don’t know the price.
I’ll look for details when I can because the forum has become so slow that I can hardly use it.

[daviemck2006]

The resistor failed on mine during the snow last year, temp control still worked and it gave warm air if you got to about 90, fan and distributation did not work. Got new resistor on e-bay, think it was about £50, 5 mins to fit it, it's up high in the drivers footwell near the clutch. Mine was a 2.2hdi sx with auto climate control.

[myglaren]

The resistor failed on mine during the snow last year, temp control still worked and it gave warm air if you got to about 90, fan and distributation did not work. Got new resistor on e-bay, think it was about £50, 5 mins to fit it, it's up high in the drivers footwell near the clutch. Mine was a 2.2hdi sx with auto climate control.

Same here a couple of years ago. Mine was £45 from the dealer. Easy fix.

Don't bin the old one (like I did) as I think that it is the output transistors that fail and could well be a very cheap replacement - under £5 I imagine.

[frenchcarnut]

Thanks for the tips thus far.

Well, checked the appropriate fuse as all I fancied doing in the light but of course that's okay.

So functionality of air conditioning seems fine (although I couldn't get the fan speed LCDs up at one point, but they came back on after a power re-cycle - just the blower not working.

So now onto the HBM / HBM resistor. Do we know what the reading on the latter should be as a check? Of course my VIN no longer matches on service.citroen.com for electrical for some reason.

[frenchcarnut]

Well I decided to get the "resistor" off and take a look. I love the way this gets called a resistor. There appears to be all manner of SMCs and a whacking great voltage regulator stuck on an equally monstrous heatsink. There's about 3 dry joints where the green connector brackets meet the SMB, but they're conducting okay. And numerous capacitors, resistors and black-box SM ICs I don't know the specs to and would find hard to remove and re-solder being SMs.

So plenty new Valeo replacement units on eBay to source (but I might ring Citroen for a laugh) and then if it's not that, try a replacement blower unit for more or less the same price.

Oh the fun of Citroening

[frenchcarnut]

£72.84 (VAT Inc) from my local dealer and in stock. So for a £10-£12 difference (after including eBay postage), I might as well pick one up locally and give it a go.

Citroen call it a "Control Module" and the parts guy knew immediately what I was talking about, so fingers crossed it is actually the problem and having taken the unit out last night, there is actually no difference in the behaviour of the climate control at all!!! Feels like it's the one, Neo!!

I'll be moaning again if it isn't

Cheers

[addo]

I'm wagering it's that big bugger which throws in the towel, rather like the Xantias. Found a cheaper thermal conductive epoxy at Farnells; enough to do quite a few cars for not many pesos.

[frenchcarnut]

I'm wagering it's that big bugger which throws in the towel, rather like the Xantias. Found a cheaper thermal conductive epoxy at Farnells; enough to do quite a few cars for not many pesos.

Eh? You mean the voltage regulator bit that sits on the fins? What's its part number and can you get it from Farnell or Maplin? EDIT - Sorry Addo, realised you're in NSW so Farnell and Maplin might not mean anything to you - just a few electrical component stores.

Looking at it, it's only three soldered pins and some paste (I have some heatsink paste used for PC chips - Artic Silver). Actually the large voltage regulator seems at least serviceable - the rest (SMC - surface mount components) I'd be more than disinclined to be bothered with!!!!


EDIT2 - Managed to get the spring clip off the VR sitting on the heatsink and break the cooling paste seal, but cannot make out any number on the component at all. Oh well!!

[addo]

It's actually bonded to the heatshink, so you need a heat conducting glue rather than just the overclocker's thermal conductive paste. Closest match carried by Farnells Oz is also made by ST but the prefix varies:

Original I have is H80NF55-08
Farnells have STP80NF55-08

They're $4.12 each here, free postage.

[frenchcarnut]

The resistor failed on mine during the snow last year, temp control still worked and it gave warm air if you got to about 90, fan and distributation did not work. Got new resistor on e-bay, think it was about £50, 5 mins to fit it, it's up high in the drivers footwell near the clutch. Mine was a 2.2hdi sx with auto climate control.

Same here a couple of years ago. Mine was £45 from the dealer. Easy fix.

Don't bin the old one (like I did) as I think that it is the output transistors that fail and could well be a very cheap replacement - under £5 I imagine.

Doubled in price now like everything else If it's the one voltage regulator/transistor that sits on the colling fins, then I can solder (and thermally paste) on a new one but can't find any identification markings on it.

[frenchcarnut]

It's actually bonded to the heatshink, so you need a heat conducting glue rather than just the overclocker's thermal conductive paste. Closest match carried by Farnells Oz is also made by ST but the prefix varies:

Original I have is H80NF55-08
Farnells have STP80NF55-08

They're $4.12 each here, free postage.

Thanks addo. Actually when you look up Farnells over here with that part number, they actually list a paste you can use. I can't use return on my browser at the moment without this site hanging but here's the UK Farnell link: http://uk.farnell.com/stmicroelectronic ... P80NF55-08" onclick="window.open(this.href);return false;

[addo]

LOL, they're cheaper over here by a good 15%. Is Australia closer to Morocco than the UK?

[frenchcarnut]

The difference with Farnell's is in the case type (TO-220 as opposed to TO-247 used by Valeo for this part) which have differing pinout dimensions and distances. I suppose I could somehow re-distance the pins somehow.

Just checked on digi-help live chat, and they say the part with that case and pin configuration (TO-247) is now obsolete, so I would have to use the Farnell configuration. For just a few quid, might give it a go and see what transpires.

And addo, did you not know? We live in "Rip-Off Britain"!!!!

[frenchcarnut]

Farnell UK = minimum £20 order <sigh>

That's how they do business in the UK.