My heater stopped working. After checking fuzes, power to final connector, I boiught a new fan. It worked, but didn't seem to be blowing as well as the previous fan. Sounded like it was on HIGH. It has stopped again, I checked fuzes and the final power connector, can not get circuit tester to light when "touched". Please how can I fix. If a easy diagram of wiring is available. If it is a wiring problem, please let me know what to say to NAPA. The chev/gm dealer in my city is little help.