Heater not blowing hot and all 4 heater vents don't close when engine is switched off or open when engine is switched on.
Fault code for lin bus fault
So we have 2 blend motor flaps and four heater vent registers(flap)
All have a 12 volt supply
All have an earth
Both load tested
Looking at diagram. We have a heater ecu.which we have a lin bus out terminal.
This lin bus goes in to one blend motor .then out to the other blend motor. Then to the other flaps.(a series set up)
I have scoped pin bus at every in and out terminal. And I get lin bus scope pattern 12v (on)0 volts (off)looks like what I would expect.
So I seem to have what the car needs to operate this system .
My question is .where should I be going now.what approach would you techs use now.
Sorry for the long post