F355 HVAC ECU

Anyone know that # of that ProAudio place to send the ECU to? Who do I ask and talk to about it, and which exactly ProAudio shop is it? There are two of them in Tampa.

 

http://www.proaudioe.com/

This is the place I used. The owner did the work himself and I believe he has done others as well.

 

So I got my repaired AC ECU back a few weeks ago. Had it repaired at the FL place many guys recommended.
The work looks very good. It did take 3 weeks though.
Picture below are all 6 chips replaced.

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So I plugged the ECU back in the car.

My Air direction works good now.
My Recirculation works good as well.

Still no AC or Hot air though. The hot water pump and the mixing valve motors still do not work. I checked the motors before and they are operational, but no power coming from the ECU. Im puzzled! what could it be????

Anyone know how to test those CHIPS on the BOARD???? How to check if they are good????????

 

Did they check the board before they sent it back or did you just ask for the chips to be replaced? You can't check the chips on the board and you'll probably need specialist equipment to test it off the board.

No AC may or may not be board-related. Could be a relay, a fuse, a pressure switch, low gas pressure, compressor clutch, etc. You may have to remind us what you have already checked.
Does your blower motor still work? If yes, you can check for voltage on the green wire on the receiver-dryer with the AC turned on? There should be a voltage if your fan is running. If yes, you may have a pressure switch or a compressor problem.

Did you replace that burnt fuseholder?

 

... and your AC is not in STOP. (Sorry, I had to qualify that statement).

If you don't have a voltage at the green wire, can you put a jumper on the compressor relay (i.e. the aft relay on the side of the inlet/recirc/fan box in the luggage compartment, to see if your compressor fires up? i.e. relay sockets 30 and 87. This will determine if the HVAC ECU is sending a command to the compressor or not. Make sure the jumper wire can handle the current going to the compressor clutch.

 

Does your HVAC control panel "STOP" button action feel normal? I see in the WSM that if the STOP button is in STOP (button illuminated), the water valve closes (and I assume the pump is commanded off). Maybe your STOP switch is permanently in STOP?

 

Ian thanks for the replies. You are always the guy helping out! No one replies usually but you. What would I do without you???

 

Anyway Ian you asked above there so much that I'm a bit lost.
Anyway my blower works. It blows air, just not hot or cold. It blows the air whatever the temperature is outside or inside the cabin. About the green wire, you have me lost Ian.
Skipping now real quick to the STOP botton. I think my STOP botton may not work properly indeed. But you think it will effect the hot and cold air if its not working properly.

I may have damaged the STOP buttom when doing the stickes on the car. The button does not iluminates, not sure if the function also works. Wonder how can i test it.

 

Not sure. We've tried to figure out how the control panel communicates with the HVAC ECU but it got very complicated.

https://www.ferrarichat.com/forum/posts/146335796/

What I was trying to get you to do is see if the HVAC ECU was giving out a command (to the compressor), but the STOP button seems like your best bet as it's not illuminating. Perhaps you can open up the case and look for physical switch damage, poorly soldered contacts, etc.

https://www.ferrarichat.com/forum/posts/146341299/

For reference, the green wire is one of the 4 wires going to the receiver-dryer in the frunk. It should have a voltage on it when the aircon is activated.

(EDIT: Now I'm not sure when the switch should illuminated... down or up... I'll have to recheck). Was your car running at the time you pushed the button?

 

I haven't personally done the panel graphic refit. It does seem tricky as there is a risk of wire damage.

https://www.ricambiamerica.com/guides/f355-hvac-replacement-panel-installation

You may be able to figure out which contacts on the back of the circuit board correspond to the power wires on the switch (for the ON/STOP command) and check the resistance across the contacts with the button up and down (?). I don't know if it's possible to put a temporary jumper wire across the switch contacts, then plug in the panel and turn on power. I don't know what kind of switch it is. It may be open or closed circuit in the ON position.

I've borrowed Andrews original pic...

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A larger version is here with the rear of the board un-reversed:

HVAC Control Panel Internals

Maybe someone can figure out which are the power contacts on the STOP switch.

 

I just remembered that Andrew's car is a 5.2, so some of the information in the links and photos may vary slightly from your car (e.g. panel wire colours). Also, not all the 5.2 wiring was known at that time (assumptions were made which turned out to be wrong).

Anyway, you may see something obviously wrong with the switch, so we might not need to worry about such things.

 

If you just want the six chips replaced, any qualified electronics repair shoud should be able to do it. Whether they will of not is another issue.

 

I got all my 6 chips replaced already. Still no AC or Hot air. I heard the 6 chips could only be checked for power once they are plugged in. I've been told you can't check them otherwise.

 

Yeah my stop bottom is kinda damaged? The LED wires as Racambi shows in his picture, mine are broken. The botton itself Im not sure if it works, Need to check it carefully and inspect it.
Ohhh and when you press it down, it lights up, and it's in ON position.

where is that Receiver-dryer in the trunk? Im trying to think what it is.

 

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Strange, I rechecked my Australian '98 5.2 car and STOP illuminated (switch down) means "I have been stopped". I don't know if your switch is faulty or not. FWIW, my switch operation agrees with the manual. There are variations in panel part numbers on these cars which don't seem to correlate to the simple degrees F or C variations (Australia has C)

Looks like the receiver dryer switch has different coloured wires from the electrical plug to the receiver/dryer itself. To find the green wire, look at the car side of the plug. Maybe you could record which wires on the car side match which wires on the switch side?

Are the receiver-dryers on the same side of the car on LHD and RHD cars?

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Yes my blower motor works ok, and blows from all directions (that has been fixed). Also I will need to test the green wire voltage on the reciever/dryer as you said. Is it green or green/black?

And No I didn't replace the burnt fuseholder. The fuse wasn't blown, just a bit melted cause it got hot from time to time. Do you think it could be bad even though it wasn't blown? I would like to replace that fuse holer anyway. Need to find out what's the best way to replace it and what people use. I mean if that 30amp fuse is bad, the blower fan wouldn't work, right.

 

When you say "at the car side" what do you mean exactly. And my receiver-drier is on the right side. Im pretty sure they kept the whole trunk design same as LHD or RHD.

 

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The plug is marked "A" in the diagram.

VN = green (black stripe)
V = green (check for 12 volts on this one (car side) with plug disconnected)
N = black
LB = blue (white stripe)

Perhaps for most of the HVAC system, but there has to be other system differences e.g. My brake master cylinder and reservoir are on the right side (same side as the pedals). Things have to be rearranged to accommodate this. The parts manual lists the support bracket for the HVAC ECU as being different. I can't remember if the HVAC computer is on a different side.

https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/355-group/f355-m2-7-1995/evaporator-unit-and-passengers-compartment-aeration.html

There are minor plumbing changes and a diffuser difference inside the cabin.

 

Sorry, had to make a few amendments in my previous messages for clarity (and mistakes).

 

When both smaller rotary switches are in AUTO and full COLD selected (blue dot) and the STOP button is in the up position on my car, with the ignition ON, my blower motor runs. When I push the STOP switch down, the blower motor stops. Does your car do the opposite?

 

Ok did some tests.

Ok tested my 30amp AC fuse and it's good. Voltage is going through it.

Also tested the green wire of the reciever-dryer.
Had the switch unluged. both rotary switches were in AUTO, on full COLD, and STOP button in UP position. Tested the green wire on the car side. There are no voltage basically. only 0.0006 basically nothing.

Also Ian can you confirm these below. Not sure how it's suppose to work.
My blower motor does not work when I have the rotary switches on AUTO. Not sure if it's suppose to blow air or not if it's selected on AUTO.
Also when I have the blower blowing air in the cabin and when I press STOP button, it doesn't stop anything. Is it suppose to??? What does the STOP botton do exactly?

 

My blower works with both knobs in AUTO with the STOP button up (i.e. un-STOP). Pushing STOP kills the fan (at least in Auto) and stops the A/C compressor operating on my car.

If possible, could you try swapping the recirculation button and the STOP button on the control panel to see if the AC operates? Look for bent pins on the button and the button base.

Perhaps the car needed to be running for this test. If you still get the same result with the car running, we should focus more on that stop button. We are getting 3 or 4 indications that the button (or system) is permanently in STOP:

No voltage going to the receiver dryer and thus no power going to the compressor.
No fan operation in Auto with STOP button in either position?
Hot water valve closed
Water pump not running.

 

I was able to access the plug (with long fingers) and ignition in ON was sufficient. I didn't need to run the car. I had around 12 volts at the pin.

Of course, a faulty relay would stop volts getting to this pin, but I think your problem is more than a faulty relay.