550 interior heater fan fails to work on 1/2/3 setting

Hi folks, wonder if anyone can assist. Recently found that the interior fan control won't work on anything but position 4, i.e. full on. Have had this before on another car where I think it was classed as the rheostat for the unit failing, £20-30 on replacement part and prob solved.

Does anyone know if there is a similar part on the 550 for the fan control which provides the 1,2 & 3 fan speeds, or is this all built into the control unit? Any repair suggestions?

Had a look around the eurospares site but couldn't find what I was after, could well have missed it though, so if anyone has any thoughts that would be grand.

cheers

Jon

 

not on a 550 but a Mondial T. Those rheostats seem to be mfgr'd by Enzo's 2.nd cousin.....probably in his will....

rik

 

Jon- The unit you need apparently has no service parts and runs around 419 pounds from Eurospares. It is number 12 on this drawing. Do not know if anybody repairs them or not. Will check with F.A.I., They just repaired my 575 SA instrument cluster. Drawing courtesy of Ricambi.

Taz
Terry Phillips
Image Unavailable, Please Login

 

Jon,

Try setting the Air Distribution Selection Knob to a position other than "aut" and see what happens.

Barry

 

doah, good advice....forgot about that

 

Mine had the same fault - you realise that the v12 engine causes some serious heat soak without the air con running on level 1 - it was fixed during the service and I think it cost a couple of hours labour on top of the unit price

 

Thanks folks for the replies, apologies for the delay in getting back to you. Alas it's not down to the auto setting, previously tried most permutations and it looks just to be the rheostat(?) I suspect that has failed, which controls the slower speed positions i.e. fan speed 1,2 & 3. Off and full on (setting 4) work fine.

Kickstart, sounds like a very similar situation, likewise I used to pretty much leave it on position 1, which keeps the temperature just right but alas it will be heating the rheostat unit.

Terry, thanks for the diagram, helped me find the same at Eurospares over here, they have it down as an evaporation unit, which is what threw me as I missed that altogether. Looking at the diagram, I was suspecting either the part you suggest, no.12 (£590 yikes), or possibly a complete control unit failure, no.7 (£800 ouch), or what caught my eye and am waiting to hear back from them, no 21 (£154 a mere trifle!), which is listed as the electric blower regulator. I had a quick chat with the mechanic and as luck would have it he's replaced a couple of the part no.21's before because of the same issue, and had a 456 unit with a duff matrix on the shelf but all else sound. So will be getting my hands on that spare to test and hopefully resolve.

Thanks for the replies and guidance, will let you know if the regulator fails to do the trick

Jon

ps interestingly, when I spoke to Ferrari re the parts, apart from saying the dash likely had to come out, likely not apparently, but the control unit (no 12 in the diagram) has a big price difference depending on whether you get a celsius or fahrenheit calibrated unit. No other difference barring the labelling, but about 50% extra for fahrenheit. Nice.

 

This might be worth a try
http://www.ferrarichat.com/forum/showthread.php?t=240199&highlight=stabilant

 

Sorry for the belated updated, but just so it completes the post, it was indeed part no.21 in the diagram above that was the issue, the blower regulator, that was at issue. Tested a spare unit and that resolved the problem.

 

Hi, we have the same issue on a 456. Can someone confirm if the parts and design are the same? Also, where is part no. 21 physically on the car and how is it reached.

On our car the fan runs full speed on all positions.

Thanks
Scott

 

Hi, I believe the 456 and 550 part no.21 in the diag are one and the same, as I think the spare I used was off a 456 matrix. Apologies for the delay in posting this but in case anyone else wonders...

On a right hand drive car, part 21 which is screwed onto the main heater unit, can be accessed via the drivers footwell, (I assume on left hand drive cars it would be the passenger footwell). There are a couple of screws from recall holding the unit in place, in typical poor design the second is behind the electrical wires and a bit of a pain to get to especially when putting back in.

 

My 1987 944 turbo developed a similar problem earlier this year but in its case, the interior fan only operated in position 4 (the highest setting). Dave's suggestion (4-20-09) was the answer. There were some oxidized components in the resistor bank which Posche placed in a vulnerable, exposed position near the firewall. Wurth Contact Cleaner cured all that.

Jon, is the Blower Regulator (part 21) a resistor bank assembly?

Barry

 

Could this part explain why my ac/heat seems like settings 1-3 are the same and 4 blows me out the rear window?

 

That's exactly what's happening, Christopher.

For A/C or heating, I turn the compressor on and leave both my 550's HVAC control knobs set to aut. I set the temperature and let the cockpit sensors regulate airflow.

When I don't need heat or A/C but just outside air, I turn off the compressor and set the controls manually (any position other than aut). I get the appropriate different fan speeds at the different settings.

I guess I'm one of the lucky ones.

Barry

 

We’re part 21 was a relatively affordable 154 GBP part in 2006, it now 752 GBP…..

 

Can be repaired and improved.

 

I can confirm that it can be repaired. Had mine done a few years ago. Contact these guys, looks like they can repair the regulator. If you read the description, it mentions Ferrrari and Diavia (manufacturer of the regulator). Mine was repaired by different company, but I can't find them anymore. When these fail, initially you lose some fan speeds, but eventually the fan won't turn off, even when the key is out of the ignition!

https://www.dmgrs.co.uk/products/mk2-45-zs-atc-transistor-pack-repair-kit-or-service-jgn000010

 

I found the company that repaired mine, just incase anybody is looking for a repair in the future.

https://www.technozen-electronics.co.uk/mg-zs-rover-45-ferrari-climate-control-repairs/