Mustang Heater Blower Motor with Cage (1965-1968) Installation Instructions
2. Drain the antifreeze out of your Mustang radiator
. There will be a mess near the heater hoses on the water pump and intake, so prepare with towels.
3. Unplug the two wires (some may have three) from the blower motor located on the passenger side of the engine bay.
4. Loosen the clamps on the Mustang heater hoses
(intake and water pump hoses). Place towels under the hoses to prevent a mess. Remove hoses. (NOTE: The water pump hose leads to the top nipple of heater core and the intake hose leads to the bottom nipple of heater core).
5. Remove the four nuts that hold the blower motor in place and set aside. Two are shown and two more are on the bottom side.
6. There is a screw that mounts the heater box on the cowl under the dash. Remove it and set aside. I kept the defroster attached to the heater box, but you will need to disconnect the cable (see step 8) on it along with the hoses. Unplug the heater blower motor switch
from the front of the heater box.
7. Loosen the Mustang heater hose clamps
that are located on the back left side of the heater box. Again, place towels underneath to prevent a mess. Hoses will slide off. I elected to replace my heater hoses while doing this project. I bought 8 feet of 5/8 hose and had plenty.
8. The cables on the heater box can be removed by removing the nut on top of the trap door mechanisms, as well as the clamps that hold the cables in place. I used vise grips and turned the nuts counter-clockwise while pulling up. Be careful not to damage these.
9. At this point the blower motor is loose from the firewall, the hoses are off, the one screw that mounts the heater box to the cowl under the dash is off and the heater cables are off (I removed the cables from the heater control panel side in this picture because I was replacing those too, though that is not necessary). The heater box should slide out. The fiberglass is brittle from its age so be careful not to bang it around. The Mustang heater core
will still have antifreeze in it so be careful.
10. Set the Mustang heater box
on the ground. The blower motor is still held in by four nuts. Remove these. The motor will slide out.
11. There is one heater to firewall seal
that fits on the new motor. Now is a good time to replace it. This joins the firewall. Slide the new blower motor back in (cage side first) and place the four nuts back on.
12. The heater cables can now be reattached to the heater box and to the defroster (if applicable). Tighten the clamps back down and reinstall those nuts on the top of the trap door mechanism. I just set it on there and tapped with a hammer. Once the cables are back in place you are ready to move the box back to the car and reinstall it, just as it came out. DON’T FORGET TO CLAMP THE HOSES BACK IN PLACE ON THE HEATER CORE AND REFILL THE RADIATOR WITH ANTIFREEZE!
13. You are now ready to plug the heater control switch back to into the resistor on the front of the heater box and into the two blower motor wires in the engine compartment.
14. Remember to check all of the steps that we did to remove the unit after you put it back in! You are now ready to fire up your new Mustang Heater Blower Motor