no rear heat

no rear heat air works good where to start? 2001 sel.

The temperature is controlled by a blend door that mixes warm with not-warm air. The first question would be : Is hot water actually warming the rear coil? Time too do some touching!

Iwill do it in the next couple of days.right now i have the front end apart doing ball joints and tie rod ends

Also: Is the fan in the rear unit working? Can you hear it spin up - and change speed- when you change the controls up front?

fan works fine.

The next quick test: When the van is warm (i.e., engine has been running - and coolant is warm), feel the heater core tubing that can be easily seen under the van, right below the rear HVAC unit. Note that there are four tubes under the van at that point: Two for engine coolant supply and return, and two for A/C refrigerant supply and return. If the van has been running for a while, two of them should be warm. If they are, this means the heater core in the rear should be warm; if you aren't getting heat, it's most like a rear blend door problem. If the tubes aren't getting warm, there's an engine coolant flow problem.