It takes a bit for the thermistor to repsond to temp changes, and again a bit for the climate control to switch modes or temps. If it's been delivereing heat, the heater core will have to cool off before the delievered air cools down.

If you have no suction, the sampler motor is bad, probably either full of lint from the insulation, or not spinning fast enough. You could have a broken hose, too, but that should be obvious, they don't usually break anywhere but at the pump.

I'd get a new sampler blower if it doesn't generate any suction.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!