Here's a head scratcher for you guys I've got a 2003

1. Check heater core for flow
Just run water through it.
2. Check heater core valve operation
Check the electrical or whatever connection there is to the heater core. If it does not work, either replace it, rewire it properly or just delete the valve.
3. Check actual coolant flow
Run the engine and keep a hand or thermometer on the coolant pipe running to the heater core.
4. Verify operation of blend door actuator
These can go bad. Make sure that your heater controls are actually moving the blend door properly. If you have coolant flow to the heater core this is more likely to be your problem. If bad, replace the actuator.

t. I don't like Grand Cherokees and this is why.

>>16457119
Unplug the inlet hose from the heater core, put into bucket, turn on jeep, see if water comes through.

You've got a plug in the system, or serious air in it that's not being pushed out of the heater core.

theres usually a heater control valve that controls coolant flow to the heater core but a quick google and i dont think cherokees have that. next option would be blend door not opening properly. feel the heater hose going to and from the firewall once youre at normal operating temp to see if they are warm and the core has flow, if it does then it could be clogged cabin filter or a bad blend door

>>16457140

Tried that no water

>>16457153
I didn't notice a valve or petcock while I was in there, but I also wasn't actively looking

Blend door maybe, but the ac worked consistently before I vented the system taking everything apart

>>16457157
if no water came out, then you could have a bad water pump.

>>16457240

If the waterpump was bad I shouldn't have been able to drive for 4 hours

So I'm getting some sort of flow, at least to the engine anyways

If it has dual zone temperature control those like to break the blend door attachment to the axle which causes the doors to drop to the closed position and then there's no air flow through the heater core and no heat. A/C works fine though.

>>16457130
2nd for blend door and actuator / control panel

My heater core exploded, so I got a go at replacing everything except the control panel.

Control panel is fucked up now so every setting also turns on the floor vents. It's a jeep thing.