Right...here we go. Had to get out of the car, grab a laptop, coffee and banana bread for this one! I apologise in advance for the likely ensuing war and peace!! However I think it could be helpful to some and helps us understand the HVAC system more. I have just spent the last hour or so trying to get to the bottom of these HVAC issues to make the hybrid HVAC/blower run 100% reliably all the time.
I have been having very weird illogical & intermittent issues with the blower in the hybrid since I bought it off Beau a few weeks back. First it didn't work at all....full stop...hot or cold....nothing. Then I removed the cabin pollen filter, cleaned all around scuttle area, around cabin pollen filter and replaced the filter. It started working on next start. Worked for a few days then stopped.
After researching around I found it was giving an AA00 (normal) condition on boot/start, then after being on for about maybe 60-90 secs you get a a/c compressor click and then it would return an AA75 error. Therefore blower error. I am just pressing both RECIRC and ECON buttons for 2-3 secs to trigger the error to pop up on the LCD display on the binnacle. You can do this at all times, anytime so doesn't need to be when you turn the ignition on. Good to diagnose an error. Can be done when driving....obviously if safe to do so!
When blower works it works well and fine. Hot or cold, slow or fast. I have played around with disconnecting the cabling/connector and cleaning the terminals but it all looks good. It worked once or twice when unplugging/re-plugging but I think that was more coincidence. When the a/c compressor clicks after 60-90 secs both the RECIRC & ECON buttons are lit and the E error comes up on the LCD. You press both buttons for 2-3 secs to see your error code. Mine is always AA75 so always blower error. Temp settings are always good, solid and accurate so don't see that the driver door mirror external temp sensor is an issue.
With the ignition on and the system is in its error condition you can unplug the connector under the glovebox. The a/c compressor polls and clicks every 5 secs. If you plug back in connector after a few clicks the error condition disappears and the process starts all over again. The ignition is on and doesn't need to be turned off and on again to reboot HVAC. You can also leave the connector unplugged when turning on the ignition and the control unit in the centre console boots up but the HAVC icons and greyed and the HVAC effectively is non responsive to any dials/settings. You can leave the ignition on and replug the connector. After 5 secs it kicks back in and boots the HVAC. All icons are dark and no longer greyed and the HVAC is operational again. Just by having that one blower connector unplugged leaves the HVAC icons greyed out or not and HVAC system enabled or disabled.
I left my connector unplugged while turning on ignition and icons were greyed. Plugged in connector and hey presto.....blower worked...icons no longer greyed. A few restart cycles quickly with on/off ignition on off on all settings auto and manual and HVAC and more importantly blower were functioning perfectly. Turned ignition off for a bit longer until you get a/c compressor click. Turned all back on....doesn't work any more! Tried previous cycle of turning on ignition/HVAC with connector unplugged.....greyed icons.....plugged in connector.....nothing!
I don't think it is the blower....or the connector...or the cabling. I was driving along the other day with blower working set to manual 75% fan speed.....carried on driving.....turned manual fan speed to off.....turned back on.....blower failed.....nothing. I can't see how that would point to connector or cabling. Maybe control unit or a really weird intermittent condition/error.
I am just going to take the control unit out of my 2007 car and swap for the hybrid one and vice versa. If I can get the 2007 car to fail and the 2003 hybrid to work then we know it must be the control unit that is actually the fault. If not then at least we know it is not the control unit and can rule that out.
Man built these machines.....or at least designed the machines that built them so I won't be beaten by this one. Man v machine!! I need the HVAC unit to be 100% reliable as it is the only thing I haven't fixed on the considerable list of faults with this car. I have the guy I provisionally sold it to coming to see it tomorrow with a view to closing the deal.
