Link block between heater valve motor and valve

I can do this for you tomorrow.

 

12mm square at the ends by 27mm long

Motor spindle hole centre 5.5mm from one end, diameter 5mm

Screw hole centre 5.5mm from same end, tapped to accept M5 grub screw which protrudes 10mm

Note you can also replace this valve with a generic Chinese part resold by Vintage Air and which, along with some connectors, wires and a bracket, is what you'll get if you spend $600 on the supercession part 63306400/A from Ferrari: https://www.ferrarichat.com/forum/posts/149791856/ post 294

 

I did install one and it worked fine, but before I got around to folding up a bracket and tidying up the wiring, I saw this utter bargain on eBay, which I installed instead:
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I will keep the generic valve as a spare - I'm also waiting for a custom-order replacement DC motor for my original valve to arrive from China, which I hope to be able to repair and will then be able to offer a rebuild service for the original parts.

 

No, the valve motor running is controlled by the AC ECU - the motor is run and stopped (the power to it is cut-off) from time to time based on the cabin temperature request and the feedback from the motor's potentiometer.

As we have recently established, the recirculation flap motor (no potentiometer) is also not continuously powered. The power to it is also cut-off some seconds after it (the flap) hits the stops. However, this does not really protect its gears against breaking as the motor is stopped only after the gears are exposed to impact caused by the sudden stall of the motor at the stops.

 

I suspect the failure mode is that the DC motor fault (in my case, seems like a short in the winding) causes the driver to continue to supply voltage as it sees no change in the output from the potentiometer, which then causes the driver to fail. Those DC motors are a £3 part, but unfortunately they are not available off the shelf with the same connectors anymore.

btw it was £62.40 with a voucher code - the breaker obviously didn't really know what they were selling. I contacted them directly to buy some more parts that weren't listed on eBay, but unsurprisingly they didn't have much left.

 

With the part on the car, use a multimeter with back testing probes to test that the voltage between the blue wire and ground varies as the motor turns.

 

The motors and the valves are still available as separate units. The Ferrari's motor/valve assembly was custom made by someone using a Bosch motor used in some Alfas and a Volkswagen valve.

Alfa/Ferrari motor - Bosch 0 390 721 006 (the shaft needs to be shortened):
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Looks like can be used (Renault 7701030385), Bosch 0 390 721 003 (the brass gear needs to be removed):
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You can google for both above motors. One new Bosch 0 390 721 003 is currently also sold on Ebay (https://www.ebay.com/itm/204172322608?_skw=Bosch+0+390+721+003&itmmeta=01JA73TTF9G7GVT4DY63YM6YG3&hash=item2f899e6730:g:ETMAAOSwuoRmjis6&itmprp=enc%3AAQAJAAAA0HoV3kP08IDx%2BKZ9MfhVJKlY%2BgTnmAc6sA18oYMhlgqSgCHyklixWChEsABgHzjGj8SRyVTLK8kGH3M82pTxFCftN6NsRS5CWoXFsWEqN3EJYi8qeUZ8l%2B87BbpvUyaqpkS6eTWV3IssQs4L1mpCkRS8DaCWqazdmJf%2BMrpaq5s7BAVzhc6jxsLWXmh42lg5Xj9L1MdF1plk3bCcHEP6n%2FFIKAjE4nCgP3nBlDohB%2FTTybDpOqBASCAFtQLMlpnxWbSmIOjapI9AXR2J9Tdpgco%3D%7Ctkp%3ABk9SR9yn6-PRZA)

The valve is Volkswagen p/n 171819809E, easily available and cheap. Needs part of its body to be cut-off (as what Ferrari did) and its arm needs to be cut shorter and bent at 90 deg.
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You ca also test the potentiometer on the bench by running the motor (make sure you disconnect it before it hits its stops) and monitoring the resistance change between the pot's middle and one of the pins next to it. The resistance change should be smooth and without breaks (an analogue ohmmeter is better for this test). The second picture below shows what resistance I measured with the valve fully closed (the coupling block very close to the stop on the motor).

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A company called "Vintage Air" (San Antonio, TX: https://vintageair.com/gen-ii-servo-heater-control-valve-replacement-kit/) make heater valve replacement kits which are also sold by Summit Racing (https://www.summitracing.com/search/part-type/heater-valves?page=1). One of the Vintage Air models shown on the Summit website (p/n 461170, $59) is described as being a 5-wire type which may mean that it has a built-in potentiometer:
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If this 5-wire model has a pot inside (Vintage Air should be able to confirm), then this model could probably work in the 348 and 355 with a suitable conversion to the wiring and a custom made bracket.

 

Yes, any of these can be used as a source for the likely failure point, the internal DC motor. It will be easier to simply swap that part over than to modify the Alfa/Renault part to work in the 355.

I am trying to find a reliable source for brand new DC motors with the correct pinion and connector block, however it is proving difficult.