[Pontiac1976]

GM Cars / Trucks , Caddys fall in hear
around 81 in the truck switch the plastic chrome switches.
around 78 most cars switch to plastic chrome switches.
around 87-92 small cars had some plastic black or inner panels colors

as said bennylava

I've taken them apart a few times in an effort to understand what keeps going wrong. I've noticed several things:

1. The bendy parts inside, bend too far. Now proper contact is no longer made. Tried of taking them apart to bend them back.

2. The copper in there turns green, and proper contact is no longer made.

3. The chrome flakes off. Looks pretty terrible when I've got the rest of the truck looking pretty good, for the most part.

4. This could be related to number one, but it may not be. The part you press, the switch lever itself, somehow manages to get pressed too far into the rest of the switch. It's not supposed to go in there at all, they're just up or down switches. But through normal use, and the way that the switch is shaped, the tendency is for people to slightly press them inwards when they use them. Not intentionally of course, it seems to just happen and I've noticed it over time as I observed these problems in an attempt to fix them. This finally wears them out inside, as it was not meant to be pushed in repeatedly. And then, proper contact is no longer made. Switch flakes out and quits working half the time.

This more true with the later years and the Dorman aftermarket replacments. But If you try to be more careful and genially pressing the button they last longer time Gm made them to last 3-5 years on average because the average would by a new car ( they made more money selling car then parts). If you had kid played with windows or some moved the window few min or turned the car off truned the key to acc to get the window up put a heavy load on the switches wear them out much faster. The best tip any of the switches in the do the relays because the way they where wired in the day and still be careful and genially pressing the button and they will last a lot longer. Same goes servicing the motor if you ask most people how time a year they change there oil back in the day most one a year maybe 2 a year maybe some did the 4 times they should have did min.6 times year the would have been less wear on the motors cam and lifters just to because the metal and oil back then was not the best. In the med 80 -90's oil cam metal in proved big time as long as you used the proper sa oils as a lot of chepper oil would not be sa approved or may be sa approved break down to fast med 70's to early 80 cam in for cheap oils does not matter what oil as long as you change the oil when viscosity breaks as soon a you can. If the switches look like the bottom is to open stretched the copper red look or to black it a short working to hard may wear out sooner then later if you clean then shorting for years it may be ok last few more years if there's wear marks in the copper it not going to last long same goes for light sockets and bulbs hotter the bulb run the more damage to the socket, bad bulb cracked bulbs overly dim bulbs, bad grounds connection over heated wires or bulbs in some cases not replacing burnt bulbs for years.