I am working on a 1994 Chevrolet 1500 pickup and there is no heat.

Chevy vents are designed to be a perfect mouse house, they always build it near the heater blower and you have to weasel out the blower housing by prying up the unidash under the glove box, after removing the screws (make sure it is in the off position).

I am not familiar with Chevy heating/air conditioning systems. Autozone have some popular workshop manuals for free on line once you register (for free) on their website http://bit.ly/autozone_repair_info. There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online