take old one out, insert new one in after you remove the dash cluster.
The question you ask is too involved for a proper answer. You need to go to a car parts store, and get a repair manual for your car. They cost about $16.00
Disassemble the dash and open up the HVAC compartment.
If you have no dash lights at all on your 1989 S10 Blazer, a blown bulb can be the problem. You should also check the fuse.
under the dash
Behind the passenger side of the dash.
Check the fuse, then the bulbs, then the brake light switch.
Yes, but you must do some rewiring. The digital dash uses a harness in the center of the dash, while the analog one uses a harness in one of the corners.
heater core???
Under the left side of dash.
That would be the OBD I Diagnostic Connector.
There are several bulbs for dash illumination. They are attached to the backside of the dash cluster. The best way to access the bulbs would be to remove the dash cluster.
open the driver side door. look on the side of the dash there it is