I have a 99 dodge ram 1500 4x2. The heater won't blow out any hot air only cold. I recently replaced heater core because it was leaking and some of the antifreeze got into the little (air blend door actuator). It wasn't heating before I changed the heater core and its not after replacing it either. The air blend door actuator won't move the door. Im not sure if I should get any type of reading with a volt meter or not there, but I didn't. Ive checked all my fused and all are good.