355 timing actuator (air direction motor) removal
355 timing actuator (air direction motor) removal
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HardtopManual

Original Poster:

2,772 posts

185 months

Wednesday 9th October 2024
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I've been attending to a broken HVAC system on my 355 and it seems that everything that could have gone wrong, has gone wrong - faulty control unit (now repaired), faulty water valve (now replaced, hoping to find a replacement for the knackered DC motor in the old one so I can have a spare) and faulty redcirc flap motor (3D printed a new gear in polycarbonate). The "timing actuator" (blower direction motor) is also not working, but I can't for the life of me get access to the screws holding it to the HVAC unit. I've contorted myself in the footwell, removed the central air vents and the instrument binnacle, but cannot get to those screws. It looks like I might have to remove the entire HVAC unit, which I really don't want to do.

Has anyone here done it (on a RHD), and if so, how?!

Cactussed

5,342 posts

232 months

Thursday 10th October 2024
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I've managed to get the motor off. It's a c**t of a job. Ended up using a stubby Phillips head. Remove the stereo and (I think) one or 2 other things and you can do it.

I removed the window ECU and the gave me enough room to check the flap moved (which it did) and also check the motor operation.

FWIW, mine was playing up and I ended up doing a battery reset then I put the fan speed and vents to a manual setting rather than auto.
Hey presto, the motor decided to work perfectly. NFI why, but it did.

https://www.ferrarichat.com/forum/conversations/35...


HardtopManual

Original Poster:

2,772 posts

185 months

Thursday 10th October 2024
quotequote all
Ha, I just set it to manual mode and did a battery reset, lo and behold, some whirring emanated from behind the dash and my air direction motor has now joined the party, thanks Drew! My HVAC system now appears to be working properly, for the first time in years.

HardtopManual

Original Poster:

2,772 posts

185 months

Thursday 10th October 2024
quotequote all
btw if anyone needs a repair on their HVAC control unit (p/n 64324800 for future Googlers), I can recommend https://crashdata.co.uk - they charged £200 to supply and replace all the op-amp chips plus a few other components and had the board back to me in a matter of days.

Cactussed

5,342 posts

232 months

Saturday 12th October 2024
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Excellent result, and also thanks for the heads up on the fixing guys.
Presumably any other ECU / boards would also be within scope

355spider

133 posts

46 months

Sunday 13th October 2024
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My heater only works on manual also, Im not entirely sure why but a previous owner has wired up a fused tripped circuit breaker in the luggage compartment instead of the 30amp fuse popping, I’m not sure why, although it’s not trippped for a few years now so haven’t bothered looking.

Will that place be able to repair the cat ECU’s? I’m
Getting error codes for all 3 and apparently there prone to going wrong again, not bad for £1200!

HardtopManual

Original Poster:

2,772 posts

185 months

Monday 14th October 2024
quotequote all
Cactussed said:
Excellent result, and also thanks for the heads up on the fixing guys.
Presumably any other ECU / boards would also be within scope
Assuming components are still available, I don't see why not.

HardtopManual

Original Poster:

2,772 posts

185 months

Monday 14th October 2024
quotequote all
355spider said:
My heater only works on manual also, Im not entirely sure why but a previous owner has wired up a fused tripped circuit breaker in the luggage compartment instead of the 30amp fuse popping, I’m not sure why, although it’s not trippped for a few years now so haven’t bothered looking.

Will that place be able to repair the cat ECU’s? I’m
Getting error codes for all 3 and apparently there prone to going wrong again, not bad for £1200!
Cat ECUs probably not worth the faff, being very heavily potted. The cheap solution is to take the bulb out of the dash, the more expensive one is to replace with improved aftermarket units, see https://technistrada.com/catalytic-temperature-con...

gotoPzero

19,367 posts

208 months

Monday 14th October 2024
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I did this job on mine, the motor was very difficult to get too, my ribs were sore for days. but you can get it without removing anything top side. You just have to get in on the screws from the footwell.

Getting it back in was worse tbh.... so prepare yourself for that!! GL!

Reggie20

75 posts

27 months

Can I reopen this thread?
Went out in the 355 last weekend - getting a bit chilly so cranked heater control right up - no change in temperature. Fan works well, air direction switch works well but temperature doesn't change. Was this the problem you guys had? Any help much appreciated.
Thanks

gotoPzero

19,367 posts

208 months

You may need to check the motor that moves the heater valve. Remove the frunk liner and you will see the heater unit under the windscreen area.

If its the valve there are options on how to DIY repair - as the Ferrari part is expensive. There are several threads on FC - they will show you how to test etc.

However if its not that then its possibly the climate ECU. There are some driver chips that fail. I had mine repaired (AC stopped working) and used a company in Liverpool who were very good and price was very reasonable.

Its quite a complex system for such an old car and I was shocked when I started to read up on the system just how much processing goes on and its fairly smart. I think you can read the fault codes with an SD1 if you have access to one.

Reggie20

75 posts

27 months

Great - thanks for that. I'll check out the FC pages as well. 👍

Reggie20

75 posts

27 months

Thanks for that. You mentioned in an earlier post about doing a battery reset. As I'm new to 355's how do you go about doing this?
Thanks

HardtopManual

Original Poster:

2,772 posts

185 months

Turn off the battery isolator under the access panel in the front boot. Leave a few seconds. Switch back on.

I doubt that will get your heater valve working though, so you'll need to remove the carpet in the front boot and have a look at the valve. Either:

1) The valve itself is seized but the motor still works. This can be replaced with a lightly modified VW part 171-819-809/E

2) The motor is knackered. Depending on the failure mode, this may be repairable. The brushes had perished on mine. I replaced just the DC motor with one taken from a generic Bosch part fitted to various Saabs and Alfas - Bosch 390 721 005 or similar. It all comes apart with a screwdriver.

3) The HVAC ECU is knackered. This can be repaired by a company called Crash Data in the UK - https://crashdata.co.uk - IIRC I paid £200 for them to replace all the op amps and some other failed components. I then fitted heatsinks to them to try to avoid them burning out in future.

HardtopManual

Original Poster:

2,772 posts

185 months

I should add - if your motor is irreparably damaged, you can replace the whole thing with a standard 5-wire heater valve. I did this temporarily while I had the original part on the bench. Vintage Air part 461170 but you'll have to fab a bracket and sort out the wiring. As far as I can see, this is what Ferrari supply when you order supercession 63306400A from them.

Reggie20

75 posts

27 months

Brilliant - thanks Charlie, much appreciated.
👍

Cactussed

5,342 posts

232 months

F355 community rocks.
So many smart and helpful people.

Reggie20

75 posts

27 months

Couldn't agree more - thanks all.

Cactussed

5,342 posts

232 months

Yesterday (09:53)
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One other thought - there's a secondary recirculation motor in the boot.
They can fail (ask me how I know) and that stops the coolant from circulating through the heater core, which means the heater doesnt get hot, so check to see that's operating.
If not, again they're a bosch part and quite simple to swap over.