Gotta start somewhere, so I took out the controls; there are just two screws under the dash that hold it in place. Push the controls through the dash and out the bottom while navigating the cables, ducts, and wiring. Next, drain your radiator if your heater core is hooked up, and disconnect the heater hoses from the heater core. | 
As best as I could tell, it looked like the rest of the heater components needed to come out as well. The interior heater box is held to the firewall with four screws and comes out pretty easily; make sure to disconnect the two wiring plugs. The heater core/blower motor box on the engine side of the firewall is another story. The bottom left screw below the motor is hard to get to between the box and the fenderwell, so prepare for some fun. When you're through with that, you may have to loosen the bolts on the hood hinge to fender mount and pull it forward to actually remove and replace the heater core box. If so, mark where the hinge sits before loosening it so the hood alignment goes back to the way it was. |
Most of the cables that operate the heater were no longer hooked up to their intended destinations, but luckily they were still clamped in place, so before I totally disassembled everything for cleaning and paint, I marked where they went, because I knew I wouldn't remember later. | 
Between cleaning and giving both heater boxes fresh coats of semi-gloss black paint, I started to rebuild the controls. It seems barbaric, but the knobs on the pot metal levers need to be broken off, but it's easily done with a pair of pliers. |
The metal sticker on the panel's face needs to be peeled off; be careful not to damage the housing. Also, my assembly was in such disarray that the lever housing separated from the chrome housing since the mushroomed heads on the back side weren't doing their jobs too well, but try to keep yours together if possible. | 
Thoroughly clean the chrome housing with soap and water and make sure all the old adhesive has come off. While being careful with the outside edge of the housing and the "indicator window," scuff and smooth out any pits with fine-grit sandpaper. With the window masked up, use Krylon #1403 Dull Aluminum spray paint to bring the control housing back to life. |
The Dull Aluminum is real close to the silver GM used on many parts. When it's dry, take a rag with a little bit of paint thinner or some fine (#0000) steel wool and run it along the outside edge to reveal the chrome. | 
Once the Krylon dries, apply the new decal in the right direction with clean and steady hands, but be careful-it's a tight fit. |
After dismantling the lever assembly, I cleaned and painted the housing and installed the new levers and bushings. The new pin goes in from the bottom like so. The thinner bushings go on the outside of the outside two levers, and the shorter of the two long bushings goes between the bottom two levers. All the cable pins point down now. If the levers don't go through the front panel with the same spacing as the slots, rearrange the bushings until they do. | |