No heat on passenger side

Good morning,

When you command heat and cool, does the passenger side blend door move back and forth?

https://www.2carpros.com/articles/replace-blend-door-motor

If it does, then the heater core is clogged and must be replaced.

If it does not, then it could be wiring to the actuator itself not allowing the door to move.

https://www.2carpros.com/articles/how-to-check-wiring

Roy

Have not installed a new heater core yet. Blocked off the lines going to the rear heater core and plenty of good heat coming out of the front. Opened the lines to the back and heat goes away. Seems like the heater core up front works okay. Just not sure why it goes away when the lines are opened to the rear of the van.

Try flushing the front core. Remove the 2 hoses to the core and use a garden hose to flush back and forth several times until you get a nice even flow both ways.

Roy

I have flushed the front heater core twice now and it’s blowing hot air up front. It’s only when I open the lines to the rear that I lose heat. Rear lines are clear and I have installed a new rear heater core. It doesn’t make any sense.

There is nothing wrong with the rear core.

It is the front core that is bad.

Roy