Air Condition knobb not working

When I turn the knobb on my 1991 318i it does not blow any air on the first and second fan speed, but when I go all the way to the highest speed the air blows out fine. What could be wrong?

It's the 'blower motor resistor' block. open the hood, remove the 'firewall' cover below the wipers,
CAREFULLY remove the plastic cover over the blower motor in the center there. the resistor block slides/plugs right into the housing in the middle of the blower motor...have some fun.......jb.

Jeff, I got into the compartment that houses the blower motor. it has two fans and one motor with some electircal wires in the middle. I am confused as to if I need to remove the motor out to get to the resistor. The motor has two wires connected to it. One of those two wire's connection is visible at front and easy to disconnect. But the otherone seems to go to the back of the motor. I'm stuck, what next? pls help

your adventure is almost over ! The blower resistor
is directly in the middle, just below the motor's armature case [ the round metal 'can' between the two 'squirrel cages'] DON'T UNPLUG ANY WIRES,
there's no need. The resistor block unplugs from housing [pull up and out] - [it's curved slightly to follow the conture of the blower housing].....you might want to get the replacement first and you should be able to see what I'm attempting to describe so poorly, but you'll find it very easy....jeff

ok. but there are two kinds of resistors. One of them is a 4 spade connectors and the other is a 4 round pin connectors; neither of which the manual specifies. I will try again. thanks jeff

'85 - '92 E30's only take the flat spade style blower
resistor blocks [ no matter what a parts book sez ],
i think the '84 cars produced with the earlier type heater core/valve use this resistor but aren't certain
the 4 'spade' block is for you...........................jb.