Originally Posted by
silky16v
plus if you leave the vents control pointing towards the windscreen the fan always blows to keep it from misting up (I may stand corrected on this yet)
This is because the later (89 >) Sierras had a modified heater control lever, which had an additional switch that interrupted the power to the blower if the lever were in the 'off' position. Even with the blower dial set to 'off', the blower would still run but at a low speed if the air flow lever is set above the lowest position.
