Ac works but when I turn temperture up no heat 1999 expidition

shudnt hav done that-u caused corrosion--now u need to take um out and see if their salvagable--getta haynes manual or sec629-ur local library

Fix your car right away by clicking the link I attached Secure Download HONDA ODYSSEY SERVICE REPAIR MANUAL 1999 2000 2001 2002...

your blend door actuator is either broken, or isnt getting power. This unit either isn't getting power or the mechanism is damaged. This is a typical issue with these vehicles.

WELL TURN ON AC MAX COLD HIGH TO SEE IF COOLANT FANS TURN ON.IF NOT YOUR REFRIGERANT SO LOW THAT THE AC REFRIGERANT PRESSURE SENSOR WONT CLOSE CIRCUIT TO TURN ON COOLING FANS.MEANING YOU NEED HAVE AC CHECKED AND CHARGED.ALSO CHECK COMPRESSOR FOR POWER IF NOT YOU HAVE BLOWED FUSE OR BAD RELAY.IF FUSE AND RELAY GOOD YOUR AC COMPRESSOR CLUTCH COIL OPEN OR THE AC CONTROL SWITCH IS BAD.IF COMPRESSOR IS RUNNING WHEN YOU TURN ON AC YOUR AIR TEMPERATURE ACTUATOR NOT WORKING.

THE TEMPERTURE SENSOR IS BAD CAUSES BOTH

idler control valve or Vaqium leack

put a pipe clamp on one of the feed pipes for the heater that will shut if off

3 words come to Mind. Heater Blend Door

its a very hard job to explain how to do i highly suggest you take if to your mechanic to fix a very technical complicated job to do your self .

replace the blower motor