355 The End? Evaporator Unit #63307220

And another one...

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To be clear, the top unit is my OE. The bottom unit is the ebay (360 / 430) unit.

When I removed my unit jumpers 6 - 8 were 'on'. Was #5 bumped during the repair of the chips? Who knows?

I tried it with 5 - 8 'on' and it made no difference.

 

Yes, that is clear from the postings.

 

I will set the 5 - 8 switches on and clean up the solder joints as Ian suggests and try it again later in the day.

 

Here are a couple of pictures that might be a bit more clear and detailed.

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I've marked some pin numbers on the reverse

 

The 355 and the 360 boards look very much the same except for the 6 chips which are in different housings on the 360 unit. Looks like an improvement in an attempt to solve the issue with frequent failures (overheating) of the earlier SMD chips. Unless the large chip in the 360 unit is programmed differently, it should work in the 355.

The 360 ECU may also have a problem (blown chips?) and this could be the reason why it is not working. I think it is worth keeping and, if finally diagnosed to have bad chips, send it for repair.

 

Re- soldered the power joints.
Moved the dip switch on #5 to on
Re-installed.
Same result.

I have switched HVAC control panels and no improvement
I have swapped fan power relays (the big one in the air box) and no improvement.
I have verified power to the HVAC control panel
I have verified power to the Climate ECU

Pretty sure the ECU is cooked in some way and I intend to send it ECU_Doctors as the next step

https://www.ecudoctors.com/collections/ferrari-355-1996-1999/products/ferrari-355-diavia-hvac-a-c-climate-control-br-ecu-64324800-repair#

Sad in the Auto Scientific did the last repair and it has a lifetime warranty, but pretty sure they only replace the 6 chips and no diagnostic work. This seems deeper.

 

ECU Doctors just sent their diagnostics report. Thoughts?

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Difficult to say without knowing which power transistor and which motor driver. If the power transistor was supplying power to the the driver chips, that might fix most of your problems. The "motor driver" sounds like one of your replaced driver chips has failed. Did you replace any of the actuators after the first ECU repair?

 

That's how I read it. I was expecting a lot more detail. If it is the main power transistor then I guess nothing else would get power?

They have not repaired it yet and the e-mail said they would contact me for repair instructions.....so maybe today?

I have not replaced any of the actuators. I did however, apply 12 volts* to each to ensure they work correctly and operate freely. That includes:

Air diverter motor
Re-circ flap motor
Blower fan
Hot water pump
Hot water valve.

* Having a model train transformer with reversible & variable DC voltage is a required tool. haha....

 

...and they just called. The power transistor that is out was the main transistor and he said nothing would operate with that failed.

Apparently they can test the "motor drivers" separately without power. One was in op....he has no idea which ones do what. Just that one did not work. I would guess that is the air diverter one as that was the first to go out.

So. Being rebuilt now and should have it by end of next week they say. $818 with shipping.

 

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Just installed the ECU. Turned the car on. *gulp*

Everything seems to run as it should.
Fan speeds work.
Diverter motor works
AC kicks in.

I'll try the rest (heater and re-circ) this weekend during a scheduled drive, but things are looking up.

It's very very early, but ECU Doctors seem to have a repair that works.

Hey Dave! I'll send your HVAC panel back tomorrow!

 

Fabulous. Hope it lasts another 20 years. With so many problems, it did make sense that it was an ECU problem (especially after the power checks were ok).

Did you send them the unit with the dipswitches in the correct positions? Hopefully they left them in the right positions

 

I sent them the unit with switches 5, 6, 7, 8 set to on.

It is sealed and if I look I lose the 5 year warranty, otherwise I would open it up and look.

Still need to run it for awhile before I declare 100% success, but this is the best it's been in a long time.

Thanks again guys for all the help. Much appreciated.

The place I sent it to was (NFI):

Specialized ECU Repair
941 NE 48th Street
Oakland Park, FL 33334
954.652.1496
https://www.ecudoctors.com