Technical 2008 Eleganza Dual Climate spotty fan

[danishbacon]

Hi, I've been having an issue where the fan is sometimes on, sometimes only on low (even if high speed selected) and sometimes off entirely. Wiggling the two connectors that attach to the heater ECU (denso) and putting pressure on them sideways or between the two, usually gets it to blow properly. Sprayed with contact cleaner and was working fine while the whole thing was still humid with the stuff. Any ideas on how to fix?

these are the two connectors that then putting pressure on make the fan (sometimes) work again.

Any help appreciated

 

[Bernievarian]

How do they look internally when disconnected ? You may try to give the female part (it's always the female) a 'pinch' with a long nose plier, clean the 'male' (they're always durty) part with sone fine sand paper (nails paper file works dam good), re-assemble and report ...

I suppose you already checked the resistor pack or is it a full auto AC ??

BRs, Bernie

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[DGPunto]

There's a guide with pictures worth reading here: https://www.fiatforum.com/grande-pu...ater-fan-wiring-loom.html?344602=#post3425921

 

[danishbacon]

How do they look internally when disconnected ? You may try to give the female part (it's always the female) a 'pinch' with a long nose plier, clean the 'male' (they're always durty) part with sone fine sand paper (nails paper file works dam good), re-assemble and report ...

I suppose you already checked the resistor pack or is it a full auto AC ??

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)

Cheers Bernie, they look OK disconnected, not melting or anything nasty. Some oxidation but nothing that I would assume to be causing the problem. Pinching and sanding did not help.

I popped the ECU/Heater unit and it looks OK (but it's all sealed up).

When I tug on the loom in certain directions and with some force everything powers up....as long as I keep tugging on it.

It's auto AC.

I suppose next try then is replacing the whole of the wiring loom?

 

[Bernievarian]

Orange & Black is incoming power from relay and fuse box, Red and Black is modulated power going to the fan. The light blue/green and light blue/black is command line from the AC unit. Have you inspected those aswell ? How about the fans side of the loom ??
M072 is the power controler, N085 is the fan

BRs, Bernie

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[danishbacon]

Hi Bernie, thanks again for that input. The problem still persists though I've not investigated further. Again always goes back to working (either at variable speed, fully functional or a fixed speed irrespective of what the control panel says) if I wiggle, disconnect, reconnect partially. If someone sits on passenger and bumps a foot on loom it might go off again.

Loom replacement involves removing whole dash and costs approx £350 from either indy or Fiat.

Had considered cutting old plugs and crimping new ones on but not sure if that's viable. Any other ideas?

I looked at the diagram you provided and not sure I fully understand.

Is M072 the Denso ECU/Heater part with two main plugs coming in and one smaller plug headed (presumably) to fan?

Cheers

 

[AndyRKett]

Where are you pulling on these wires ? The wires going into the back of the denso control unit from which you operate the settings of the climate control, are certainly not accessible by someone’s feet bumping them just by sitting in the passenger seat.

On the other hand the wiring to the PW module that controls the fan speed on climate models is, pulling the wires about is in my opinion a red herring, you will be moving the connectors about also, and it’s likely there is a broken or dry joint inside the module that you are making and breaking by pulling the wires about.

This is a receipe for a fire as weak joints in high current circuits can cause the joint to heat up, and overheat.

Common fault here would be the PWM device that controls the fan speed, being at fault. If you phone fiats parts department for a price, be sure to have some smelling salts handy to revive you afterwards

 

[danishbacon]

Where are you pulling on these wires ? The wires going into the back of the denso control unit from which you operate the settings of the climate control, are certainly not accessible by someone’s feet bumping them just by sitting in the passenger seat.

On the other hand the wiring to the PW module that controls the fan speed on climate models is, pulling the wires about is in my opinion a red herring, you will be moving the connectors about also, and it’s likely there is a broken or dry joint inside the module that you are making and breaking by pulling the wires about.

This is a receipe for a fire as weak joints in high current circuits can cause the joint to heat up, and overheat.

Common fault here would be the PWM device that controls the fan speed, being at fault. If you phone fiats parts department for a price, be sure to have some smelling salts handy to revive you afterwards

Cheers Andy. The plugs I'm referring to are the ones coming into part number 55702441, the resistor/heater assembly just next to the blower, in the footwell of the passenger side. I'm going to order a replacement resistor as it's an easy swap and see if it fixes the problem. The plugs I've inspected and though still a bit corroded please to be quite solid. If the resistor does not fix then I can only imagine it being a faulty loom and will have to cough up the £300 odd to fix as the car is otherwise sound and I can't drive in the winder without defogging winds.

 

[Optikal]

Hi mate, not sure if this will help very much but I also have an Eleganza and had a very similar problem. Here's my thread on how I ended up having to rewire some new connectors.

https://www.fiatforum.com/grande-punto/458206-eleganza-heater-not-blowing.html

 

[AndyRKett]

Cheers Andy. The plugs I'm referring to are the ones coming into part number 55702441, the resistor/heater assembly just next to the blower, in the footwell of the passenger side. I'm going to order a replacement resistor as it's an easy swap and see if it fixes the problem. The plugs I've inspected and though still a bit corroded please to be quite solid. If the resistor does not fix then I can only imagine it being a faulty loom and will have to cough up the £300 odd to fix as the car is otherwise sound and I can't drive in the winder without defogging winds.

Just to reiterate, your car, having climate control, does not have a resistor, it has a PWM Module and these are much more expensive than a resistor.

As the grande is essentially a corsa and uses several similar components in the aircon/heater unit, you might find a cheap alternative with a Vauxhall sticker on it.

 

[danishbacon]

Thanks Andy and Optikal for the input.

Andy, the part in question is 55702441 or A.430.008.00 - It's not the small resistor present in the dial climate control units but it's still for whatever reason referred to as a heater/blower control resistor. I understand that it's pulse controlled but that's where my knowledge stops.

An update. I for some reason assumed that this particular part should not be at fault given that it's basically a 'sealed' unit. Some kind of a heat sink like metal piece, hooked to a base which is epoxied in place with 6 individual pins sticking out. It didn't 'make sense' given the symptoms that there would be a fault in there or poor connection so I focused on the loom.

I just took delivery today of a cheapo Chinese made replacement part with the 55702441 code. I installed it and voila, full control of the ac/heater speeds. Something odd happened though, the temperature gauge would spike on ignition and throw a check radiator fluid temperature, turn engine off immediately message. Temp then came back down and no more problem. It did that twice and I decided to remove the new part and put old one back in, temp spike gone.

I'm returning the cheapo and have ordered a proper Denso manufactured one with the A.430.008.00 sticker (though it was only advertised as 55702441 which brought up as Andy suggested, a Corsa part).

Hopefully that will do the trick and I will report back with results. Thanks again, you've all been very helpful.

 

[danishbacon]

For reference and to keep everything in one place, I was able to locate a wiring wire loom repair kit as well:

https://www.euspares.co.uk/search-autoparts?keyword=55702441

 

[danishbacon]

The new OE part fixed the problem.

 

[Bernievarian]

Thanks for the update !

BRs, Bernie