1990 Chevrolet Blazer Q&A

1990 Chevrolet Blazer Question: heater prblem

First my heat wasnt coming out at all so i figured the fan was not working took fan out got a new one and still nothing so i traced the power wire up to a little metal box with a plastic plug then started moving heater speed from low to high heard a clicking traced it to the metal box just wondering if this box could be the problem i know i am getting power and a good ground and i know my new fan works -
Answer 1
I had the same problem with my 91 blazer last winter. We stopped at a gas station and the engine was smoking, It turned out all i needed was anti-freeze and the heat worked again. Before that i replaced the fan and thermostat. Try checking the anit-freeze cuz i had the same problem -