Best way to remove dashboard blanking plate to install defroster switch?

[WissaMan]

My 77 New Yorker has the rear defroster (wires type), all the wiring in the dash, and I have the switch. But the dashboard does not have the spot cutout for the switch. I guess the dashboard must've been replaced at one point from a car that didn't have it. Unfortunately, it doesn't appear that the blank spot is just a plate that snaps in out. Looks like it has to be cut.

What is a good, safe way to do this. I really don't want to damage the panel, but I really DO want the rear defroster to work

 

[Ross Wooldridge]

It's possible that there is a breakout tab, which will be easier to see from the rear - you'll have to get up and under to check.

If it IS there (I can't be sure, others will know for sure), then use a very small drill bit (1/16th or smaller) to mark the CORNERS from behind - drill through carefully. If there is no breakout tab, then you'll have to decide where you want the switch to sit.

Once you do, then again, mark the critical corners from behind with the drill as noted above.

Either way, then you'll have a visual of the place you're mounting the switch, or the breakout tab's dimensions. Mark the outside with layers of heavy tape to make a channel where the tab's lines are, and then proceed carefully from there with a VERY sharp utility blade, and score the lines in the channel you've made using a straight edge to help you. Score repeatedly - take you time - many scorings and and you'll be through. Don't rush it.

Alternatively, mark the corners, and use a hole saw that is undersized to NOT go over the dimensions of the breakout tab, and then you can score the lines as noted above, cut to the corners from the hole you've made and use your fingers to break the edges out.

Pictures of the dash AND your switch would help us advise you better.

 

[WissaMan]

I have it apart, I'll get a picture tomorrow. From the front side, it kinda looks like the blank plate is a separate piece. But from the back it looks like it's just all one molded piece. One thing I didn't think of doing was looking at the spot where the clock is, as that was an option too, which this dash has. That may give some clue to whether the dash was made with the openings according to the options, or if they were removed as needed and how that was done.

 

[CBODY67]

How is the switch retained to the trim panel? Might there be a thin bead of plastic to indicate where the hole that is not there might be?

Just curious,
CBODY67

 

[WissaMan]

It appears it does not get mounted in the dash behind the front panel, like the radio, hvac controls, clock, etc. Rather, it gets mounted to the front panel itself. And the fact that it has little nubs on the back of its face plate, it would appear the blank plate does not get completely cut out. Instead, it looks like only a part of it gets cut and the defrost switch face drops in from the front while the switch itself screws to it from the back once it's dropped in. Then two speed nuts or push on clips go on the nubs to hold it in place. Further confirmation of this is the fact that the blanking plate sits about 3mm deeper than the other openings, so that once the switch face plate is dropped in, it will be flush with the other controls.

So, what to do to make sure I drill the holes and cut out the shape properly?

Well of course, I used my 3d printer (when you have a hammer, everything looks like a nail, right?) to fab a template that I will use as a guide to drill the holes and score for the cuts. May seem a bit extreme, but I've only got one shot at doing it right so I don't want to screw it up. Though I still may, once it comes time for the cutting I just gotta remember....patients, patients, patients!

 

[WissaMan]

Success! It took a drill, a utility knife, a mini torch, and several hours if you include designing and printing the template. Seems like a crazy amount of effort just to mount a switch, but eh, I did most of it in the evening when normal guys are probably watching football...

 

[Ross Wooldridge]

Nicely done!