Starter on 1998 buick lasabre

The stop light fuse on a 1998 Buick LeSabre is located in the rear fuse box. To access it, open the trunk and locate the fuse panel on the driver's side of the trunk. The stop light fuse is labeled "STOP LP" and is located in the top row, second from the left. It is a 15-amp fuse.

Pump is inside the gas tank

The starter relay is inside the fuse box under the hood the solenoid is built on the starter motor.

Your best bet aside from a mechanic doing it would be to use Google, Google something like "Replace starter in 1991 Lasabre" If lucky one of the many car forums or even a video on You Tube will come up .

you have to remove the compressor, the pulley bracket will bolt to where the compressor was, it should line up with the threads from the original bolts.

It's built into the "fuel pump modual" You have to drop the fuel tank =(

The blower resistor is part of the blower module which is located on top of the blowercase under the hood. Just by the blower motor , hope you find it.. It will also have 2 plugs on it..

I found the diagram in my owner's manual.
I replaced the belt on mine just 2 days ago. All you need to do is remove one bolt from the lower motor mount and remove the spacer. After you relieve the belt tensioner, the belt will slip right through the gap. Don't forget to support the engine before removing the bolt. As a backup I took a photo of the belt with my digital camera beforehand... just in case.

Tank

Under the passenger side dash behind the and to the left of the blower motor. Not a fun part to remove but it can be done.