OK, My K5 gets a little cool when the heater won't blow on high. I have replaced the blower motor, dash switch, and the coil thingy in the evap box under the hood. The motor will work fine on 1-3, but when you switch to 4 it dies completely. Whats next, someone mentioned a blower motor relay, but I have no idea where that bad boy is. Help please....... Thanks.