So my ASI repaired unit looks to have failed. Lost control of recirc motor & air diverter motor. I do have the "lifetimne warranty" and will be sending it back, Just curious how you guys are getting on with the rebuild.
It will be interesting to see if this is a failure of one of the newly-installed op amps. Given that there are six of them installed in the unit and we only ever seem to see the one responsible for blower directional fail, it does suggest that there's some other factor causing that chip to fail, rather than some inherent issue with the chip itself.
I just installed my ASI fixed computer and the air direction motor and water valve still do not work. I think it is something in the system. My outside temp sensor does work, not sure about inside air sensor. Changing console control panel did not help. I notice several owners, including myself, had the problem start after turning off the battery. Who else had this happen after a battery disconnect?
In my case it was the hot water valve actuator that failed. All other features function normally. I'm not that interested in fixing it since I really don't drive the spider with the top in cooler weather. And it is simple enough to wire the valve to operate independently. If these fail repeatedly I would suspect that some other component in the system is drawing excessive current causing the control amp to fail.
So last night, before pulling the ECU, I tried the whole mess again. The directional blower was stuck on defrost. Speed control works fine The recirc motor was in-op ( it works if I put 12 volts directly to it. ) If I turn the temp knob to all heat, the heater valve kicks in. Out of pure ****s & giggles, I started the car. The air direction now works. Speed control works fine The recirc flap closed and remained so The heater system worked the A/C did not. Defrost worked in manual & in auto except for the A/C part Is there a logic difference for the HVAC whether the engine is running or not????
Look what I picked up yesterday! Sorry about the long wait guys, between a trip to Vegas and a Florida hurricane all of us got backed up on getting this project completed. 6 new OP AMPS installed. We did not find time or $ to trace the output of each AMP so I still dont know what AMP goes to which motor. Total installed price was $95 for the labor, same place I mentioned earlier. Owner of the shop said he was very interested in other folks sending theirs in if they want the same work done, I'll share details if you are interested. I should get around to installing this weekend. I am also going to 12v power each of the motors to test them before installing the ECU and make sure they are all operating correctly as well. Image Unavailable, Please Login
A little digging suggests that Ferrari changed their source of this part during manufacture of the 430. I'm struggling to confirm this and am happy to be proven wrong, however it appears that: Part no. 204068, listed for 360 & 430, is made by Modulo, same manufacturer as our 355 boards. Part no. 132097, listed for 430 only, is made by Delphi. The Delphi part no. is 463009200. Both part numbers look externally identical to the 355 part (64324800). Has anyone tried a 360 or 430 HVAC ECU in a 355? It may be that the Delphi part is more reliable than the Modulo one.
SUCCESS! I now have a 100% functional HVAC system in my 1995 Rossa Barchetta F355. Symptoms: 1. The re-circulation flap would not open or close despite a new Ricambi boss installed. (tested - no 12v power from the ECU) 2. Cold or moderately cold air from the vents, despite a full system clean/vac and charge after engine out last year. This one was weird as it would get cool when starting the car and 10-15 minutes later would start blowing warm air. What I did: 1. Diagnosed the 3 motors in the luggage compartment with a power-probe and multi-meter to make sure these all worked. 2. Replaced the 6x op-amps on the ECU board with brand new ones. I got a deal on 10x op-amps so I just replaced all of them. Used a local pro-audio shop to replace the chips since they were surface mount. He replaced and tested with an ohm meter to check they were connected correctly to the ECU board on the back side. We did not spend any $ to trace the op-amps to the outputs on the ECU which I would have liked to have seen so I still dont know which op-amp powers which motor. Side note: Once I had everything plugged back in, discovered I was low in R134a so I charged up the system. I will address this in a new thread. Some diagnostic work: Without the ECU plugged in and power switch off on the car, I used a power-probe to check the 3 motors in the luggage compartment 1. The re-circulation flap opens and closes with 12 volts now that the boss has been replaced. Make sure the flap is installed right, it easily falls out the hole on the opposite side of the boss. The flap goes up and down easily with 12volts. Reverse the positive/negative to make it go opposite direction. 2. The "pump" that draws hot water from the engine compartment just runs with 12volts applied. It draws 0.6 amps running with the ECU turning the pump on per my clamp meter. 3. The mixing valve opens/closes with 12v applied to the 1 and 5 pins. Reverse the positive/negative to move the opposite direction. OHMS on the motor is about 47. OHMS on the 2-3-4 pins are 1580 regardless of position I tested. OHMS on the 3-4 pins are 1580 open and about 6-7 closed (not sure which but there is a major difference and does adjust downwards/upwards as it moves position) Observations to help others: 1. The re-circulation flap has a mind of its own - It runs on some ECU program. With the button pressed in, it stays closed and cycles open for a minute or two. There is some info in the WSM about this I can reference if someone needs this but it seems to be temperature/timing dependent. With the button out, it still stays closed and then opens. Good news is I did watch it run a complete open-close cycle by itself. 2. The internal venting works perfectly - defrost, feet, face settings all work correctly. Auto works fine as well. 3. Fan speed works perfectly on all settings. 4. With the fan speed on 4, direction on face (or any really), stop not in, setting the cool dial to the blue dot makes the hotwater valve close all the way and shuts off the pump next to the mixing valve. With the re-circulation flap closed and parked in the garage running, the vent temperature eventually got down to 42 degrees once I put about have a can of r134 in it. With this same setting driving around the temp got up to about 48. Watching the re-circulation flap open and then close (about 2-3 minutes) probably to let in a change of fresh air, the temp jumped to about 60 and then went back down to 42 or so withing a minute or two once the flap closed again. 5. If I move the dial all the way to red same settings as above, the mixing value moves all the way over to the stop in the opposite direction and the small motor next to it turns on. Air temp out the vents gets close to 100 but did not test for long. 6. Playing around with the various temperature settings - I noticed any time the mixing valve is not set to 100% closed, the pump motor would run. I also noticed the mixing value would adjust its position to various points between open and closed so the ECU is obviously trying to mix the air temp to reach the desired temp inside the cabin, the mixing value is not a 100% open or closed scenario, it is fully variable. I would say I spent about 5-6 hours total on messing around with this. Thanks for the help everyone! I hope this helps everyone else with their HVAC issues as well! (oh yeah and Mike at Proaudio said he would love to do more ECU repairs if you want to mail him your ECU and TC chips - He charged $150 for the work the chips from China were $35 or so)
Some pics. Recirculation flap program per WSM. Temp while driving on with setting on blue and re-circulation button pushed. Also temp while parked in garage in the shade. Outside temp was around 88-89 and it was drizzling and humid as hell (Florida!) Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Quick and dirty diagnostic: (obviously remove all the trunk lining to access the hvac systems) 1. Start the car with the ECU still installed and set the temp dial to blue dot, face, stop button off, recirc button pressed in, fan speed to 4. The lights in the STOP and RECIC buttons should be lit if you push them in, the power for this panel comes from the ECU. 2. Check your R134 level and make sure this is good first. If the compressor cant cool this is all for nothing. The compressor should be engaged with the setting on blue. 3. Use a multi meter and check to see if there is voltage at the recirc motor. Just unplug it and and see if there is voltage coming from the ECU. - No voltage = broken ECU Op-amp (or worse, ECU is dead) 4. Move the temp dial from blue dot to red dot and watch the mixing valve and pump motor. the valve should swing all the way from one side to the other. The pump motor should also engage and the pipes will get really hot assuming the car is up to temp. 5. Move the temp setting to 72 (or middle for you metric folks) and watch the mixing valve again, it should set somewhere close to closed or in the middle. The pump should still run. If you set it back to blue dot it should close on pump turn off. If you stand in front of the car and look down at the pump close would be metal bar at 2 o'clock position and open would be at 11 o'clock position. If the mixing valve is not moving from side to side when you move the temp setting from blue to red then the op-amps could be blown. If the pump is not turning on then same - blown op-amps. At this point I would disconnect the ECU, turn the car power off and manually probe the 1-5 circuits on the mixing valve and motor to see if they turn. If they move/power on then your ECU is broken. If your valve is closed and compressor is fully charged and are still getting warm air your valve might be physically broken - you can test this by setting on blue and just clamping the line running into the valve and use a temp gauge to see if the temperature drops out the vents. I don't have a diagnostic for the diverter valve, sorry mine just works.
Not sure I follow all this. If both the Stop and Recir button are pressed the recir flap should close and stay closed. Release (only) the Recirc button and the flap should open and stay open.
Pretty sure if you press stop everything quits working. I can check with the clamp meter tonight. I'll power the car (not start) and press stop button in and check for voltage to the re-circulation flap motor. I'll try pressing and releasing the re-circ button while stop is off and on as well.
Guys, I just got back to florida and finally have the time to catch up. I wanted to keep my promise to post my notes to fix the AC ECU on the f355. The first pic are the 6 chips that control different components related to the ac system in the 355 and 360, possibly the 430 models to. I have the plugs shown so you can see where the chips are located on the board in relation to the plugs. I was able to narrow down what 3 of the chips job is. The #4 controls the recirc flap. #5 which is the one I replaced controls the HOT and Cold valve, and #6 controls the stepper motor. The second pic is how I checked them, but its been so long I don't remember much unless I study it again. Good luck and I hope this helps Image Unavailable, Please Login Image Unavailable, Please Login
In Summary: Chip #4 controls the recirc flap. Chip #5 controls the HOT and Cold valve Chip #6 controls the stepper motor (diverter inside the cabin = feet/face/defrost) Is this correct? Image Unavailable, Please Login
Tested mine. Engine running, stop button pressed. Recir button pressed closes the flap. Released and the flap opens. Press again and the flap closes again. Note. Fan speed and vent selection in manual modes. Fan = off. Vent selection, anything but Auto.
John - I reproduced this behavior last night. The engine HAS to be running, it does not work if the car is only powered on. For everyone following this thread - Re-circulation flap test: Engine running. Air direction setting - anything other than auto. fan speed setting - set to zero. (not auto or 1,2,3,4) STOP button pressed in Temp setting - anything. Pressing the re-circulation button in closes the flap. Pressing the button out opens the flap. This is repeatable over and over with the above settings.
Time to close her up and drive her again, I am done here... At this point everything is 100% functional in my car. All diagnostics are posted as well as break downs of the chips on the ECU board to replace if something is not working. You can basically test everything with some very simple diagnostic work following my instructions. Mike at Proaudio said he is happy to do the solder work if anyone wants their ECU serviced. The chips are cheap at a few $ each. Happy to help you guys connect on this. I am going to stay subscribed to this thread so if anyone has any questions please let me know. Thanks everyone for the help!
It's been about 8 months since I started this thread so I figured I'd post an update. I bought my car a couple years ago and did all the drivetrain work the car needed at the time first (engine out, valves, guides, seats, cam belts, acc belts, Hill bearings, gaskets, seals, filters, motor mounts, trans mounts, all hoses, all vacuum lines, all fluids, etc.). Already had Fabspeed headers and Tubi exhaust. Suspension, brakes, clutch, and trans were all solid. My HVAC was a disaster so it was next on the list. I started tackling it in Spring of 2016. Blower worked. Interior HVAC control panel tested ok. All air blew out of defrost no matter what even though the air diverter stepper motor tested ok. The A/C compressor worked and the air blew cold...at the windshield only. The heat did not work. The exterior temp sensor was ok. The cabin temp sensor was ok (left of steering wheel). The treated air sensor was bad. The aux water pump tested ok but didn't turn on when it should. The re-circ stepper motor was bad and the boss was broken. My heater valve motor tested ok but didn't work when controlled by the system. I started by replacing anything that actually tested bad (treated air sensor, recirc stepper motor, and I replaced the broken recirc boss with the improved Hill piece). After replacing these three items and resetting the HVAC system through battery disconnect and relearn with the key on as per instructions in other FCHAT threads, the system unfortunately continued to function the same way with the same issues. This was the point I was at last June when I started this thread. I had narrowed the problem down to the HVAC ECU being faulty and was about to send it off to ASI for a rebuild and just needed to know if the car could be driven while the ECU was removed for rebuild. No issues there. While my ECU was off at ASI for rebuild, this thread grew some legs and turned in to an excellent reference source on how to replace the six op-amp chips on the HVAC ECU that control the recirc flap stepper motor, heater valve motor, interior diverter drum stepper motor, aux water pump, blower, and fan on the interior temp sensor. I would have loved to try to tackle the ECU rebuild myself with the new excellent information posted earlier in this thread, but I had already sent it off to ASI for repair at that point and had paid for the lifetime warranty. Once I re-installed my rebuilt HVAC ECU, almost everything worked. Aux water pump worked, recirc flap worked, interior air diverter (cold A/C to the face!!) worked, and the heater valve motor worked. While the heater valve motor worked, it wasn't actuating the heater valve. Upon closer inspection, it appears that one of the previous owners in an attempt to fix the heat disassembled the heater valve assembly and replaced only the motor with the Saab part (shaft was shortened/cut). When the motor was replaced, the metal block that connects the motor shaft to the actual heater valve wasn't reinstalled. It was long gone meaning the working motor wasn't actually attached to the valve even though the motor was working properly. All of you probably know that these heater valve assemblies that contain the motor, metal block on the end of the shaft, and the actual valve are hard to come by. Luckily a fellow Fchatter had one for sale at a reasonable price. Once I made the purchase and added the missing piece, everything worked perfectly. I now have an extra working heater valve and motor but not a complete extra assembly due to missing metal block. Something tells me the motor will come in handy someday. Finally, my entire HVAC system works properly in manual and auto mode. The ASI ECU rebuild is still solid with lots of use over about an 8 month period. I took the time to write all of this in hopes it will help someone searching threads for help diagnosing and resolving HVAC issues at some point. I had nearly every common issue/symptom with the HVAC system when I started this process and didn't want to just blindly throw parts at it. Through research, testing each part, and replacing or rebuilding failed parts, I finally have a working system. Good luck to anyone reading this chasing F355 HVAC gremlins.
Congratulations on your successes, Brian, and thanks for your contribution/feedback... Now I'm off to sell my car immediately.. I never knew so much could go wrong with the HVAC system But seriously... This thread is an inspiration for those with a seemingly "terminal" HVAC system. Thanks, Cheers
Thanks for following up at the end of your journey. Threads that just stop near the end of successful conclusion with no final result drive me nuts. Well done.
