I just finished a restoration on a 3 Speed Heater Box out of a 1966 Ford Mustang. The internal metal components had the typical rust from years of moisture and leaking heater cores. It was also stuffed with leaves. In the past, I even found them packed with nesting material from mice. The case had a lot of small cracks, and most of the metal clip tabs broke when I removed them. The case becomes brittle from being exposed to years of moisture that swells the case material. After disassembly, I carefully sand blasted all the parts. Then I primed and painted all the internal metal parts with Rustoleum paint. The tedious part was repairing all the cracks and all the clip tabs. Only three tabs were useable. Even as careful as I am, the tabs break very easily, and you have to be equally careful when putting them back on. After all the repairs were made, I masked and painted the external metal parts, and then painted a clear coat on the entire box. I added extra coats of clear coat to the inside to seal the box from further moisture damage. While everything was drying I cleaned the original 3 speed heater switch, heater resister, and the original heater control cables. I also, cleaned and tested the heater blower motor. After which, I reassembled the heater box with new foam gaskets, new heater core, and a new heater plenum. Each new clip had to be fitted to avoid stressing the heater box case, or break the remaining original tabs. When everything was back together, I bench tested the heater box, and everything worked like new. The heater box is for sale on eBay. It will fit a later 1965 Mustang as well. Late 1965 Mustangs came with 3 speed heater motors, so this box will fit. There are two ways to determine if your Mustang has a 3 speed heater. The first one is that a 2 speed switch has two positions, and shuts off in the middle position. The 3 speed switch has three positions, and shuts off at the far left position. The quicker way is to simple look at the face of the heater box. If you see wires plugged into the face of it, then it is a 3 speed heater box.
Parts List.
- 64-68 Heater Box Case Clamps Part # C0DF-19A779-A
- 64-68 Heater Core (without A/C) Part # C5DZ-18476-A
- 64-68 Heater Gaskets Part # C5ZZ-18500-A
- 64-68 Heater Plenum Part # C5ZZ-18471-A
All of these parts are available from Scott Drake Restoration Parts
FOR SALE on eBay