is it vaccum controlled on 99 jeep heating system/where is it located
The temperature adjustment is electrical. The blend doors are vacuum. Do you have no heat or is it not going where you want it to?
i have no heat at all. flushed heater core and new thermostat. it has to be electrical or blend doors are not opening
I checked RockAuto.com and your Jeep has a blend door - not a valve in the heater hose. You can go there to see what it looks like. When it is shut, air goes through the heater core. When it opens, cold air goes around. Look at the picture, find the door and shut it for the winter. It could be vacuum. it could be electric that controls the door and you'll find that out when you locate the door.
Looking for a Used Grand Cherokee in your area?
CarGurus has 71,106 nationwide Grand Cherokee listings starting at $995.
Search Jeep Grand Cherokee Questions
Jeep Grand Cherokee Experts