For other members
Some Tests you can do
To check the transitor, turn the transistor upside down, with the leads facing you and the flat face towards you, the left terminal is the base, the centre terminal is the collector and the right hand terminal is the emitter. Set your meter to the Diode test function, connect the black lead of your meter to the Base terminal and then connect the Red Lead of your meter to the collector and emitter terminals in turn and you should get a diode test indication for both junctions from the Base. Also connect the meter test leads between the Collector and Emitter terminals, there should not be any readings between these two terminals.
To test the Car loom and Chassis Ground
Test: 1 probe to the ground pin socket on the car loom (the one pin 9 connects to) and the other to the outer ring of the cigarette lighter. (IGN off and with IGN On), set the Multimeter to Ohms
Outcome: 5-9 Ohms measured, I tested both the Ill GND & HVAC GND, GND is good
Test: Capless sidelight bulb, ILL 12V & ILL GND ; HVAC 12V & HVAC GND, IGN On , DRL's on
Outcome: Both ILL and HVAC 12 V illustrated the same intensity of light, no issues with the 12v Plug
Test: Verify 12V HVAC / ILL is going to the circuit board, via 12V pins/GND's, IGN On , DRL's on
Outcome: Verified 12V with multimeter
Test: Check Fuses
Outcome: Verified HTR 7.5 amp Fuse is intact / CIG 15 amp is intact