I've got this Heat/AC control (pictured) that works fine, but definitely needs some cosmetic help. At the very least, the lens needs polishing and the two bottom knobs need re-chroming. I spent some time messing with it today, and I haven't figured out how to get the lens and knobs off it without possibly destroying something.

I also did some checking for a NOS unit (hey, you never know) and came up empty-handed. I also did a search here and came up only with threads about heater hoses, heater boxes... you get the idea.

Any advice is appreciated from someone who has done this.

I'm working on a non-ac version for a 71 RR. I used a dremel to slice the 4 tabs, repainted the back flat black, silver on the lip, then carefully polished the front of the lense. You have to be very careful not to wipe off the ink on the back side.

I bought a cordless dremel off amazon (its pretty cool to not have the cord dangling) and the kit came with buffing wheel. I used 3m plastic polishing compound to do the final polish.

then remelt or epoxy the corners back down.

Thanks CDP.

Did you do anything with the two chrome-plated plastic (I think) knobs? I can't see how they come off the shafts.

In the second picture, you take that washer like thing off, then the arms, then pull the arm with knob forwards and out the slot. Hope that makes sense

OK, with much trepidation, I got this thing apart. The lens has some foggy/scratched places on the outside where it was rubbed with a dirty, dry cloth... or something.

I'm thinking of polishing the outside only (because the inside looks good and I don't want to re-do the lettering) with a headlight polishing kit, starting with the finest grit polish (which would be the thhird and final step if I were polishing headlights). Any other recommendations for polishing it?

You could always try the Maguier's plastic cleaner and polish - two different steps . . . then I would use a good wax/cleaner to finish it off . . . but only on the outside part - inside has the lettering on it, that you don't want to rub off

Thanks. Is this the stuff... #10 and #17?

https://www.amazon.com/Meguiars-10-Plastic-Polish-Cleaner/dp/B0002VAZ34

I use this
https://www.amazon.com/Meguiars-Clear-Pl...eguiars+plastic
and this
https://www.amazon.com/Meguiars-Mirror-G...eguiars+plastic

Not sure if your link is the same stuff with newer packaging. Works great

Yes, that is the same stuff; thank you. There seems to be consensus, so I'm ordering it now.

do not polish the back of the lens! the markings will come off. I used 3m lens polish/protector cause I already had it.

On the knobs, wenol polish, but 0000 steel wool, etc, will work also.

Yup that is the stuff, but I have the older packaging . . . good luck, take your time, might take a few applications . . . post some pics when you are done. As was said, ONLY do the front of the lens.

Here is my followup after using the Meguiar's #10 and #17.

This stuff definitely helped, but did not remove all the scratches. It added a luster or shine to the plastic face that definitely wasn't there before, so despite the fact that some scratches remain, the piece definitely looks better. Since the heater controls are down low and off to the side (as opposed to a speedometer lens, which is in the driver's line of sight at all times) I deemed the lens "good enough" and put the HVAC controls back together.

I tried taking pics of the lens, but I couldn't get one that really showed the difference.

So, would I do this again? Yes, but only if the lens is not in direct line of vision. Otherwise, I'd investigate other ways of polishing clear plastic, or possibly see if an instrument restoration shop would polish the lens.

You could probably use some 1000 to 2000 grit sandpaper, then polish. I've done this on headlights several times without issues. 3m micro finishing compound, followed back with meguiars would probably get the scratches out.