replaced the alternator, now my heat is not coming out of the vents when turned on on 2001 BMW 740i

i just replaced the alternator... and i was turning my ac to make sure it turn on. so when i tried the heating system, it was blowing cold air. can someone tell me if there was a sensor or something i didnt put back while replacing the alternator. i also disconnected the battery while replacing the alternator. did i or do i have to program something for it to work. it was working before. confuzed as hell

by in Roseville, CA on February 20, 2011
1 answer 1 comment
ANSWER by on February 21, 2011
SHOULD HAVE BEEN A LIQUID COOLED ALTERNATOR. WHEN YOU REPLACED THE ALTERNATOR AND REFILLED THE COOLANT. YOU HAVE TO BLEED THE COOLING SYSTEM WHEN YOU FILL IT OR ELSE COOLANT WILL NOT CIRCULATE AND HEATER WIL NOT WORK. THIS COULD ALSO CAUSE ENGINE OVERHEAT WITHOUT GAUGE SHOWING OVERHEATING. TRY BLEEDING WHEN YOU FILL THE COOLANT. THERE SHOULD BE A BLEEDER ON TOP OF EXPANSION TANK AREA. REMOVE BLEEDER, FILL COOLANT UNTILL IT COMES OUT. SCREW BLEEDER BACK IN, START VEHICLE AND OPEN BLEEDER UNTILL NO BUBBLES. THEN HAVE HEATER ON FULL HEAT DEFROST. GOOD LUCK
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COMMENT by on February 21, 2011
Well I have good news. Itz blowing hot air again. I did not think of bleeding the tank. I did not notice a little leak. I can see why I would have to bleed the line. Im going to look into cleaning out my tank. Thank u for ur advice:).