Well I ordered the wrong part so if anyone needs a check control box, I have an extra Does anyone have a diagram for the internals? I'm unclear what portion regulates the heater valve. I can hear the relay click inside, but there are other components which I assume regulate the power to that terminal I'm just not sure which they are.
Yes see above - all were in spec! This is why I've been super stumped. It's likely the HVAC control but given the cost of these things I wanted to be a little more sure or try to diagnose what I have.
I sent a picture of the HVAC relay to my friend who is an EE and he laughed and said you can get all the parts for it online. He figures whatever is wrong he can fix it, so I'm gonna have him check it out and report back. All signs point to a single component may have failed (since everything for the ground switching comes back to this part) and he's already ordered a new one. I hope to report back shortly after he takes a look.
The click is the micro relay that triggers the ac clutch. And if you zoom into my wiring diagram you can see a rough schematic of the hvac ecu.
Excellent photos and information, afterburner -- thanks for posting. Adding the F PN and Bosch PN for future searching: Ferrari Part Number = 61079400 Bosch Part Number = 1147328034
Thanks for those and I’m using your wiring diagram to help. I’ve pretty much verified all the inputs are correct, and looking at the pins on the actual board, it appears the transistor is responsible for switching the ground. So what I can tell is that it’s the transistor that’s bad which makes me nervous since it’s pretty unusual for one to stop working. But my buddy is going to take a look.
On my car, the main power supply to the HVAC via connector 12 had burned out years ago so I bypassed it: Image Unavailable, Please Login
My buddy came over tonight and we looked over the unit. All the input signals were good, but for some reason the grounded output never changes and we can't get the light to blink. He's taking the unit home to look over the schematics. He thinks one of the amplifiers is bad since it wasn't giving the readings he expected. Best case he fixes it, worst case I have to spend the money anyway to get a new one.
So the heater valve relay (the right one of the three) never clicks when you change the temp setting?
Correct. We have determined that all the input signals (temp sensors) are in spec, we have determined that the heater control is correctly providing 0K - 10K ohms to pins 5 and 6 as you spin it, but the output at the HVAC ECU never changes. Based on the wiring diagram, you would expect the ground on pin IV to "pulse" based on changing the temp but it does not. Also - and this makes no sense to me - but if I remove ALL THREE of the relays under the dash, the bulb I have connected to the heater valve control still stays on. The only thing that shuts off that test light is unplugging the HVAC ECU. Here's another thing afterburner - in my car, the relay to the heater valve is the leftmost relay (drivers side) and there is a red paint mark on that socket. If I move the relay to the rightmost position, the fan comes on full blast.
Albert -- I think afterburner is asking a bit of a different question. Since you've reported that the heater valve always stays closed even with the heater valve relay removed from its socket = bad sign for the HVAC ECU regardless, but what afterburner is asking is "when you ask for heat, does the heater valve relay click (change state) like it should (even though the heater valve still always wrongly stays "on")?" Even with a bad HVAC ECU, the heater valve relay should change state whenever any pushbutton other than "OFF" is pressed.
I thought I was answering but re-reading I did a bad job LOL. Assuming we are talking about the purple relay (SIPEA 0440) in his wiring diagram - then no it does not click. What I was trying to say (badly) is that it looks like the signal to click would be coming from the HVAC ECU, Pin IV (br/w) and going to terminal 87a on the Heater Valve Relay. At least that's how I interpret it to work. This is the part that's sort of confusing to me and my friend - what exactly provides the "click" for the heater valve connector. The heater pot is changing the resistance coming in to Pin 5 of the HVAC relay. From there, something must be altering the signal going out of pin IV. That splits off and goes from Pin IV to the heater valve AND to the relay which I'm just not clear why that works that way.
With ignition on, the heater valve has 12V on it. The negative is controlled by the ecu (pulse, off or on) and the power is fed via the relay. Since, when you you unplug the ECU, the negative is broken, we can assume that the both the positive and the negative wiring is intact - and therefore the ecu isn't switching but instead provides a permanent ground connection. Do I make sense? Last test - if you remove the ecu but install the heater relay - does the light come on? It shouldn't because that would indicate a ground short between the valve and the relay. My bad - you're car is a LHD - all reversed from my RHD. The relevant relay here is indeed marked with a red dot. Sorry for that.
That is a bad thing. No, the way it should work is that the large MN wire in the C12 connector should always be +12V whenever the key is "on". This puts +12V onto terminal 85 of the heater valve relay (SIPEA 0440). When the "OFF" pushbutton is pressed, the GV wire leaving the pushbutton unit 60 is connected to nothing (and this wire goes to terminal 86 of the heater valve relay) = the heater valve relay is not energized. When any other pushbutton is pressed, the GV wire is connected to ground = puts ground on terminal 86 of the heater valve relay = energizes the heater valve relay. Do you have this behavior? (The heater valve relay does not change state when going from requesting AC to requesting heat -- it always stays energized whenever any pushbutton other than "OFF" is pressed).
I can't thank you enough for the help with this - I went out and tested at the terminals. First - is there a decoder for wire colors on Ferrari? I've seen MN and GV and other abbreviations but I'm not sure what they correspond to on Urs chart. I was able to understand what you were asking however. For this test, the ECU is out of the car (and at my friends house currently getting a diagram drawn up) if that matters. First - I do hear the relay click when I press the buttons. So that's good. Here is the behavior of the test light based on your question which is similar but not exact Ignition on, STOP pressed = Power to terminal 86 on Relay = Light ON at Heater Valve Connector (relay clicks) A/C on = Power to Terminal 86 on Relay = Light ON at Heater Valve Connector (relay clicks) A/E button pressed = NO power at Terminal 86 = Light OFF at Heater Valve Connector (no click) DEF button pressed = NO power at Terminal 86 = Light OFF at Heater Valve Connector (no click) So this seems to be the behavior you describe except the A/C and A/E buttons act differently. This still seems to be pointing towards the ECU internals as being the problem, does it? I assume something inside the HVAC ECU prompts the ground coming off terminal IV of the ECU to cycle on/off causing the light to blink. Should the SIPEA 0440 relay click like a blinker when the heater control knob is rotated?
The best way to test is full cold or full heat - you need to hear the ac clutch engage and disengage and the heater valve do the opposite, within a few seconds delay when you rotate the knob between extremes. For testing at the moment, the in-between is irrelevant to see if the system is operational. The heater valve will pulse if only little heat is needed (same as the ac cycles faster or slower depending on the required coldness), but stay open when the temperature difference between the sensor and your desired input is large. So when anything other than off is pressed, the heater valve or AC will do whatever it takes to get the desired temp. Should you chose the current ambient temp, nothing will happen with either of them. By the way - I admit I do not understand how the valve control is supposed to work. It seems to me that at position 6 on the ECU connector with the two brown/white wires connected to it would always have the heater valve energised if the ignition is on - I don't understand how this could ground cold be broken. But then I am not an electrician. Steve, could you please shed some light on that? It seems to me that: 1) the MB wire from the relay should go directly to the valve, and 2) the ECU output signal in pin IV should be a + and go t0 pin 85 of the valve relay. It is indeed wired up like it's drawn on the diagram... HELP!
I don't like very much of this. With the key "on" (with the HVAC ECU present or not), you should always have +12V power at terminal 86 of the heater valve relay. However, I did a more careful reading of the HVAC system in your OM Section 2, and, while it isn't very clear, it does say that the heater valve can work when the STOP button is pressed so the heater valve relay clicking there seems OK, but the heater valve relay not clicking for the A/E and DEF buttons seems wrong as that would always hold the heater valve closed (i.e., no heat possible for those buttons). : Have you confirmed that the the wire colors (and number of wires) going to the female terminals of relay sockets for relays c, m, and n match afterburner's schematic and/or the 1984 MondialQV wiring diagram book? Have you also confirmed the relay types for relays c, m, and n are correct?
Steve - no doubting your competence on the subject matter but from my information below are the conditions of workings for the Mondial system (my summary of all available information): Image Unavailable, Please Login Heat to my knowledge is very well possible for all except OFF button. PS: I think the reason for the heater solenoid to be open when not energized is that you can bleed the cooling system without ignition on and be sure it's open.
The way the heater valve logic works is the BR (white-red) wire at the heater valve is always +12V when the key is "on". When the heater valve relay is unenergized, this puts a constant ground signal onto the MB (brown-white) wire at the heater valve via terminal 87a of the heater valve relay, and always holds the heater valve closed (regardless of what the HVAC ECU is doing or not doing). When the heater valve relay is energized, this removes the constant ground supplied from terminal 87a of the heater valve relay and then pin IV of the HVAC ECU controls what the heater valve does -- i.e, if the HVAC ECU has ground on pin IV (which is connected to the MB wire), then the heater valve is held closed. If the HVAC ECU has no ground signal (i.e., a +12V signal) on pin IV = the heater valve opens (because both terminals of the heater valve are at +12V = no current in the heater valve coil = heater valve opens).