Technical Impossible access to the heater fan resistor

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Technical Impossible access to the heater fan resistor

DaveMcT

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I have read everything I can find on the subject including the totally useless Spanish pdf file that gives absolutely nothing helpful for left hand drive never mind right hand drive.

Has anyone done this job without removing the pedals box.

I have taken out the driver's seat for easier access (lie on floor with feet on back seat). The resistor is right up against the firewall above the pedal box. The resistor pack can be seen by moving the air recirc damper and looking up inside. But access to remove the resistor looks impossible without removing the whole pedal assembly.

Has anyone done this without removing the pedals as a complete assembly? If so how is the pedal box / assembly removed?

Someone says he disconnected the steering column and pushed the clutch pedal down, but I cannot see how this would make any difference.

I could imagine that completely removing the steering column might gain access but folks will understand I dont want that job if its not necessary.


HELP!!!
 
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This is from the Haynes manual
 

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It's one of those jobs suitable for someone with extremely long bendy arms! A real bugger to reach if you don't want to dismantle the car.
 
It's one of those jobs suitable for someone with extremely long bendy arms! A real bugger to reach if you don't want to dismantle the car.

It's not just bendy arms they'd need to be like the long arms of a chimp. No disrespect to chimps.

I've done advanced search looking for heater stuff by burrowsdeano ca't find anything relevant

I've had the driver's seat out and lay on my back. Moved the air recirc flap to look at the speed control resistors. Its clearly visible. BUT the business side of the resistor unit is so high it's impossible to reach.

Removing the pedals does not bear thinking about and access still looks restricted by the firewall. The last thing I want is all that work and still not being able to reach.

Is it possible to get better access by dropping the steering column out of the way or even removing the instrument binnacle?

Can anyone find the official Fiat method for this job?
 
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It's not just bendy arms they'd need to be like the long arms of a chimp. No disrespect to chimps.

I've done advanced search looking for heater stuff by burrowsdeano ca't find anything relevant

I've had the driver's seat out and lay on my back. Moved the air recirc flap to look at the speed control resistors. Its clearly visible. BUT the business side of the resistor unit is so high it's impossible to reach.

Removing the pedals does not bear thinking about and access still looks restricted by the firewall. The last thing I want is all that work and still not being able to reach.

Is it possible to get better access by dropping the steering column out of the way or even removing the instrument binnacle?

Can anyone find the official Fiat method for this job?


Looking at the chimp, there's too much bulk to its body for the job. I think a gibbon or Columbian Spider monkey might be better for this job... :p

More seriously, when this failed on my car, my mechanic failed on his first attempt and then had to order a long bendy tool to remove the old one to replace it... I don't think he'd rush to replace another one any time soon... No knuckles left...
 
I have all sorts of tools for getting into awkward corners but while the plug top of the resistor can be seen, there is no way to get an arm/hand up there to get even close to it. The only way Fiat could have made the access worse would have been to put it on the firewall side of the heater case.

I'm going to whip off the lower access panels and see if dropping the steering will help. But I'm not hopeful.
 
Hello,
I'm in the same boat in trying to change the resistor, looking through some (though not all) of the notes, they are from those who plainly haven't attempted this job.

This is an issue that would be a slight hassle on a LHD car, but on a RHD, it hasn't been relocated so its near impossible :)

As described elsewhere, it is quite easy to see it, ie via the re-circulation outlet in the drivers footwell and via the removal of the glovebox (easy) and fan (also quite an easy).

But seeing it is one thing, getting to the nut ended screws holding it in place, is another matter. The only access is up and behind the steering column as it exits the car in the drivers footwell.

The service manual says to disconnect the steering column, I cannot see that will make a huge difference and I would rather not if possible, due to its importance :)

I am therefore thinking there are two options, to see if a 5.5mm long nut driver can get to the bolts as my hands cannot (ps not even sure yet if the nuts are 5.5mm just hoping they are the same as the fan lock bolt?), or waggle the thing via the fan entrance until it breaks and then glue another one in its place?

As with the previous user, if people do have a better method please advise :)
 
I have just whipped off the instrument binnacle (four T10 Torx screws and three T25 screws). The instruments have a natty lever type connector which is handy as you cannot see how it fits. Anyway, there is a heavy tubular frame beneath the binnacle that supports the steering column. This blocks any access to the heater or anything else below. There is ZERO access from the top with the column in place.

The good news is that it looks like removing the column could give access to the heater resistor. Cant be more definite as I've not whipped mine out to have a look (so to speak ;) )

There is another option. When I suggested remotely mounting the resistor with its own cooling fan another contributor (sorry cant find the post so can't give credit where its due) said a PWM device would be a better option.

The heater fan fuse is 40amps. This PWM controller offers 40A (480W max) at 12V which should be ample for the heater fan. It's under £10 so there might be nicer ones for more £££s.
https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=143415663106&_sacat=0

It would need some work on the fan speed control knob to attach the potentiometer but it could be wired direct to the motor with no need to touch the speed control resistor or any of it's wiring.

I've done some forum searching - We are told the two dumbell shape control knobs bezels can be removed. Pull off the control knobs and carefully pry off the bezel. That's supposed to give access to the heater control switch. I have not tried so let us know if you do it.
 
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I have just whipped off the instrument binnacle (four T10 Torx screws and three T25 screws). The instruments have a natty lever type connector which is handy as you cannot see how it fits. Anyway, there is a heavy tubular frame beneath the binnacle that supports the steering column. This blocks any access to the heater or anything else below. There is ZERO access from the top with the column in place.

The good news is that it looks like removing the column could give access to the heater resistor. Cant be more definite as I've not whipped mine out to have a look (so to speak ;) )

There is another option. When I suggested remotely mounting the resistor with its own cooling fan another contributor (sorry cant find the post so can't give credit where its due) said a PWM device would be a better option.

The heater fan fuse is 40amps. This PWM controller offers 40A (480W max) at 12V which should be ample for the heater fan. It's under £10 so there might be nicer ones for more £££s.
https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=143415663106&_sacat=0

It would need some work on the fan speed control knob to attach the potentiometer but it could be wired direct to the motor with no need to touch the speed control resistor or any of it's wiring.

I've done some forum searching - We are told the two dumbell shape control knobs bezels can be removed. Pull off the control knobs and carefully pry off the bezel. That's supposed to give access to the heater control switch. I have not tried so let us know if you do it.
Hello,
Thanks for the great info, fitting your little 12v variable psu would be another way around the difficult access to he resistor.
When fan speed 1 did work, I did find it a little too slow, but 2 was too loud, so speed 1.5 would be a nice option :)
I doubt it could be seamlessly added to the heating controls however so would have to place the variable resister somewhere novel.
It was one thing I did like about the auto climate on my old 100Hp, in having a good range of speeds, but I didn't like the fussiness. 3 knobs and push in for air con, is within my understanding :) on my 4x4 cross.
I agree that removing the steering column would help a bit, but am weary of doing so, you are also meant to have a new bolt if you take it off? Also I had a bad experience losing steering many years ago in an escort mk4 -it was disconcerting too say the least :)
For now I have on order a flexible nut spinner and a small 5.5mm socket, if that doesn't work I will be seriously considering your variable speed option :)
 
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Some more info.

The heater control knobs pull off the spindles. Grip and pull. The amber coloured plastic pegs transmit light from the illumination bulb. Pull them out and set aside. They only fit one way but are fiddly to relocate. The dumbell cover lever off. Put a layer or three of masking tape on the dash face to protect the finish. A thin flat screedriver will pop the cover off.

The speed control switch is clipped into place. CAREFULLY wedge the bottom left tag with a suitable small scredriver. DO NOT over do it as these are the only things that retain the switch. Use another switch to push the other two clips while easing the switch upwards. It will slide out but A found parallel action pliers were handy to pull it out. The spindle is plastic so I was keen to not pull on that. There are two connectors leads Both have a push tag to release. Wires are only just long enough so take care but when released the connectors pull off easily.

You now have the speed switch that carries the control knob. Good luck with using a different potentiometer in it's place. Not impossible but will be fiddly. At least the wires are accessible so power should be easy to find. You may be able to find a male spade connector that fits the connector block contacts.

My suggestion for now:

Keep the OEM switch as it carries the speed and aircon (if you have it) control knob. No switch and the knob will just wobble around. Fan motor speed would have to be done with another sat nearby. The little circular vent just above the gear lever is ideal. Wires can be run from the PWM box to the fan motor. There should be space under the dash for the box.
 
Another option would be to work out which wire from the switch goes to which part of the resistor. Then Take a deep breath and cut all but the fan power in and the aircon power wires. Run new wires to the engine compartment and rig up a bracket for the new resistor. As said before, you would probably need a small computer case fan to keep it cool.

If you want to be really cool, extend the switch wires and fit a connector block.

None of that is simple pimple but its 100x easier than trying to get to an impossible resistor that will probably fail again.

On your concerns of the steering failing. The assistance works up to 30mph. After that there is no power assistance. When the power stops working, you simply lose the assistance at low speed. The car is usable but the steering is very heavy at parking speeds.
 
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I think I'm going to have a go at your advice, I've ordered that psu but from a UK supplier for £11 on ebay.
It can provide 40A, but that does seem alot of current for the fan, is that just for a margin?
If you think it is possible to slightly gut the dash to put in a pot instead of the switch, that would like tidy. Otherwise I was just going to splice it inbetween the resistor and fan plug, as access without the glove box in place is good.
That will mean though there are two fan switches (sort of first and second stage). The resistor pack is still working on 2, 3 and 4 is direct.
Where the pot needs to go, I can get another knob from the breakers, you were saying the shroud around the gear linkage in the middle, there is a lot of space, but it is a bit curved though?
I was thinking of a headlight or dash brightness potentiometer would work quite well?
 
Can anyone find the official Fiat method for this job?

The official Fiat method is to quote the customer such an eye-watering price for the repair that they trade the car in instead. :mad::bang:.

We all need to work together to find workarounds for these sort of issues, or these cars are going to be effectively scrap once they're more than about eight years old. Dave's idea of bypassing the existing wiring and fitting an independent controller has merit.
 
The official Fiat method is to quote the customer such an eye-watering price for the repair that they trade the car in instead. :mad::bang:.

We all need to work together to find workarounds for these sort of issues, or these cars are going to be effectively scrap once they're more than about eight years old. Dave's idea of bypassing the existing wiring and fitting an independent controller has merit.

Thanks JR :)

I really like the idea of using a PWM as it's infinitely variable and low cost. The issue is getting it to work with the original switch. A simple chocolate block will allow the wires to be run out from the OEM switch to a PWM or the remote resistor. However, the switch is a substantial multi-function device not easily replaced with other options.

Option 1A - Use the original switch to turn the fan on/off and switch the aircon. Fit a separate control knob to control the fan speed via a PVM. Not ideal but most folk only use one speed for most of the time.

Option 1B - Do away with the OEM switch and use the original knob with the PWM potentiometer. You would need to make suitable brackets to carry the "pot". Put a suitable illuminated switch on the multi switch panel to switch the Air Con on/off. The wires are all there under the OEM switch.

Option 1C - Wire resistors to the OEM speed control switch and use these to set speeds via the PWM. Resistors in series add up so they could do the same job as the rotary potentiometer. You would need to check the actual resistance values on the PVM potentiometer as it could be log scale or a linear scale.

Option 2 - Remote mount an OEM fan speed resistor under the bonnet. It works hardest at low fan speeds so add a small fan to keep it cool. Somebody might know a more elegant way to add a heat sink.
 
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Me again. I got bored so opened up the heater control knobs to do some measuring.

The switch knobs are located neatly within the dumbell cover. The spindles fit snugly to keep them down. The fan speed switch has a 6mm dia D shape spindle. It also moves in and out to switch the air con. Cars with aircon will need another switch. You could use a 100HP or Eleganza switch block that contains the extra switch for front fogs. Cost under £10 on eBay or fit a universal push button into the blank of your own switch block.

The neatest option will be to remove the OEM rotary switch and put PWM potentiometer under the speed control knob. It will need a mounting plate but how hard can that be?
Project Binky CAD to the rescue.
There is another option
The dash panel can be removed. It's not clear from this if the fan speed resistor is accessible but it probably will be. Take car, Fiat do not deburr their hidden steel work.
https://www.youtube.com/watch?v=1-G6rwnRQFI
 
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is it not the thermal fuse that blows inside the resistor pack due to the fan either failing or temporarily blocked by leaf or similar ?
 
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