here is my problem, last winter, i would turn on the heater, the fan would come on air would blow out, but it wasn't hot, it was cold. what i noticed was my temperature was different. my temp guage as i'm driving is always right in the middle('94 325is), but in the winter, as i drive it wouldn't reach the middle, it would always be closer to cold or instead of being in the middle or half way, it would be a quarter of the way. then if i'm in stop and go traffic, the gauge would go up and reach half way(normal). and the heater would blow hot air, but once i started driving, and this is in the winter, the gauge would go back down and it would be cold again. is my thermostat messed up. is it something else. anyone know how much it costs for to fix the thermostat.