1997 Ford Aerostar Aerostar Low heat on both front and rear

Sounds more like restricted heater cores.

What do the heater hoses feel like at the heater cores? Hot to the touch?, same temp?

Both heater core lines are hot and bypass valves working properly.Seems like too much cold outdoor air entering both systems.What should I check. I am very mechanically able.Very frustrated...Jim

Okay good.
Lets look at the probablity of air pockets. I think you have a stubborn one. Raise the front of the van up 3+ feet or as high as you can get it. Add coolant a few ounces at a time. Keep reving up engine, lettling it come back to idle. May take 50 times of this slow procedure.

There is a tool that snap on makes...prolly others too that attaches to the rad and puts a vacuum on the system to pull the air out. The aerostar can be a real stubborn one to bleed. The engineers didn't worry about that when they built it. I'm pretty confident that you'll nail this thing if you get the air out.

Car just seemed to be taking in only cold outside air and overpowering heater cores. Removed outdide grill that runs accross bottom of windshield and along hood.Removed and found fresh air intake opening. Sealed hole by compressing large sponge and inserting into opening.Front heat now working at about 80% of normal which is pretty good. Rear air still same(slightly warm at low air speed)Does rear air have fresh air intake also? Sounds like a damper/s issue.Any ideas. Cannot find any diagrams of ventilation or heat controls....Jim

I still think there is an air pocket in the cores. Remarkable how much the temp came back for you by blocking off the air intake duct.

I'll look for the info you requested and update when I do.