We had a drastic change in the weather the other day and the check engine light was on the next morning without the key in. I unhooked the battery, replaced the ovp relay and will re-chek in the morning when cold. The strange thing is the heater motor stopped working at the same time the ce light emerged.. I had been having trouble with it anyhow in that the thing would not stop blowing but would operate on high/low. Now it is not working at all, at any speed... Any Hints?