(T) 63 plate Panda 4x4 interior fan/blower issues

A bit of a weird one.


Wifes 63 plate Panda 4x4 diesel has around 32,000 miles on clock, had it since new.


For the last couple of months we've had issues with the ventilation.


Has the basic system with a/c.. nothing fancy, don't know if any kind of climate control was an option


All seems to work fine in terms of the basic controls, so fan speeds, a/c on/off and directing the flow


Occasionally, usually 15 to 20 minutes into a drive, the fan seems to ramp itself down so that virtually nothing is coming out of the vents. Also noticed a few times (most notably when I borrowed it to go to work in the cold snap) that right from start, I couldn't get a decent flow out of the vents even on highest setting.


To test this we've put the system on full fan, full, cold, with a/c on and driven it with icy cold air howling out of the central vents. Not touching the ventilation controls after around 15 mins, the thing ramped down over, maybe a couple of minutes until virtually nothing coming out of the vents, literally hardly enough to feel with your hand a few inches away. I then tried switching the temperature up to full heat and after a delay of around 20 to 30 seconds the fan ramped up again.


Had it to garage yesterday, but they didn't actually listen to my description I carefully gave them and so just kept it for a day and handed it back saying it was working


Any ideas ?

I had something very similar (I believe) with my 63 plate TA 4x4. The air con spooled down despite being ice cold. Too cold as it turned out. Air con pipes were white and freezing cold. Mechanic reckoned evaporator had it from memory. Don't know whether it's dash or engine out. You'd need it confirming. If it is, how badly do you want to keep it or fix it?! I didn't do either. Needed major service, brakes and tyres at some point. So that was that gone.

This might be an issue with the 'resistor pack' which is what regulates the fan speeds.

Basically speeds 1, 2 and 3 are made slower than 'full' (4) by switching in resistance into the supply.... Although if you have the same issue on full speed this may not be the case?

The resistor pack is a square green package, a little smaller than a matchbox but similar proportions, and is in a place where it is nearly impossible to reach! You can see it though if you set the heater controls to recirculate, then look up above the top of the clutch pedal-- you can see it (with a torch) through the curved plastic grille the recirc control opens.

(Hint- have someone operate the recirc control while you peer up with the torch - you'll see the bit of plastic that moves, and, when open can see the green pack beyond it. If it is failing it will look blackened and burnt instead of a uniform green. There a photo of the part here: http://www.vospers.com/parts/genuine...-resistor.html

Looking at that photo, the 'bullet' shaped component is a thermal fuse, attached to the green encapsulated part. If this gets too hot then an internal solder pellet melts, releasing a spring, and it goes open circuit.

Thanks for the comments... Car was supposed to be being picked up today from home by the garage so they could drive it and check out the issue.... needless to say, no sign of them yet !


I just get the feeling they are not at all interested in looking at it because its not something simple, it actually needs a bit of thinking/investigation which I guess your average dealership just isn't interested in/capable of these days


I'm not sure it quite fits either description. The effect is still there with the air con off and, yes, it happens if the fan is on the full setting... in fact that is how I've been reliably re-creating the effect.


One other thing that I forgot to mention is that sometimes you also get a mist out of the vents when the effect occurs, I don't think we've got a aircon leak as this has been going on a while now and when the thing is working well with the aircon on, the air out of the vents is very cold

Bumping this back up, as I have recently taken delivery of a 'new' (pre-reg'd in May) 4x4 MJ and I too get 'odd' things with the blower fan. It does indeed appear that the blower 'slows down' as I drive, and it definitely speeds up under braking

I wonder if this is in fact all part of the newest alternators from Bosch and part of the stop/start strategy? Bosch's latest technology means that, once the battery drain from starting the engine has been replaced, the alternator hardly does anything when the car is driving along, and the electrics are all driven from the battery. When the car is in overrun (weight of car is pushing the engine) or when the brakes are pressed (both these can be sensed by the brake switch or a change in vacuum in the brake servo) the alternator is re-engaged which brings the battery voltage back up again (and so will speed up the fan).

This is covered here from Bosch - item 8 in the diagram is labelled 'Alternator with braking energy recovery'

I cannot find anything to say if Fiat use this or not, but the system is used in other cars with Bosch ECUs and alternators, and Fiat use Bosch ECUs and s/s/ systems. By taking the added load of the alternator out of the system when not needed, it adds an extra percent or two of mpg. (The battery voltage is also monitored by the system and the alternator can be brought back into play if the battery level is dropping too far)

Sounds a bit like the vacuum-powered wipers on Fords from the 1940s and 1950s. Anybody else remember those?

Is the Plenum dry? (the channel below the wipers where the suspension top mounts live) If its full of water it may be the fan sucking water in. There are two duck billed drains that need cleaning out every few months. This could explain the mist you see.

I suspect you are spot on Pete - my previous Audi had this, as does our S2000. Checked the latter with a voltmeter whilse driving and it is also load controlled, as switching the heated seats on re-engages the full alternator level and voltage climbs back up to 14.3v from a 'coasting' 12.5v or so. Has the same impact on the fan speed as well.

Check the obvious too. Do you have a simple blockage that get worse as air pressure increases as you drive. Pull the pollen filter and check that too!

Hi.
Under normal operation when switching on a high load device like heated rear window, heated seats or filament type headlights the voltage across the battery should momentarily drop. It is slightly slower to respond on systems that use the body computer to control the alternator charge rate. A drop of 1.5 volts won't make the fan give a really noticeable reduction in output.
I'd be looking elsewhere, a blockage as has been said, plenums full of water or leaves, the pollen filter and then look at the switch, resistor pack and the fan motor itself.
One scenario to think about is if the charge rate was dropping really badly you'd see this as dull headlights and a battery that would need a charge or a jump start.