Heater core replacement on a 1996 s10 - 1996 Chevrolet S-10 Pickup

SOURCE: 1999 S10 Chevy truck

you will have to remove the dash assembly and then the heater/a/c box it is in the hvac module.

SOURCE: 1996 chevy s10 heater not blowing hot air

heater core or leak on cooling system

SOURCE: 1994 CHEVY BLAZER W/AC S10 HEATER CORE

The link below helped with mine and has pictures as well. Good luck!
http://www.sytyarchives.com/howto/viewarticle.php?article_name=heater_core.php&dir=climate_controls

SOURCE: 2001 chevy blazer s10 need to replace heater core

http://www.fixya.com/cars/t3722263-change_heater_core_in_2001_chevy_blazer

SOURCE: how do you replace the heater core on a 1998 S10

I am a GM Certified Auto Service Technician. You need to loosen steering column, take apart all dash components, pull back complete dash then you have to sneak core out and then in new one. Tough job. Have done twice. Hated it both times.