I have an 03 Grand Caravan with rear A/C and heater, last week the steel tubes running to the rear heater rusted out, so I replaced them. Now I don't have any heat in the back, just blows cold air with temp control on high heat. The front heater works fine, too cold to see if the rear A/C works. I think there is a vapour lock in the system and not sure how to get it out. Any thoughts out there?

 

It can take some time to work the air out of the rear, They make a large funnel that attaches to the radiator fill neck, I fill that and run the engine at 2000 rpm til she stops bubbling.