GMC Repair: 2000 GMC Safari Heater trouble, blower motor resistor, gmc safari

Question
Good night,

I have a 2000 GMC Safari (4,3 Vortec).  This morning, the front heater never started (and didn't still...).  I hear "clicking noise" near the blower when I set the fan speed (low-med-high).  I checked the black and white wires at the rear of the controls and I could read around 12 volts.

Can you help me?

Thanks,

Answer
Hi
Assuming I am correctly reading this, the Blower is inoperative? Not the heater, but the blower.
IF SO, I would HIGHLY suspect the the Blower motor resistor/relay.
It is located JUST below the blower motor outside under hood.
There are SOME vans that MAY require the removal of the windshield washer and coolant level resivoir to gain access to the resistor.
I Hope this helps
Pawl