There is an electrical switch screwed into the side of the transfer case that completes the circuit when you shift it into 4-wheel drive.
That switch is screewed into the top of the transfur case that's bolted to the rear of the transmission.
The actuator is located on the front axle.
The temp blend door actuator is broken.
Depends on what type of 1991 Buick you're referring to...
It is a front wheel drive.
You don't, you replace it.
On the front left of the engine.
165432 #1 cylinder is left front
yes
You will have to remove the transmission and torque converter from the car to get to the front seal.
It is under the battery rack. Remove the battery and there are three bolts in the engine bay and one in the fender well.
front and back both should be 5 X 5