I started looking on ebay, but then found the same stuff cheaper from Digikey, and I trust them a whole lot more. Mouser too. Especially when I added up shipping, I bought 4 switches (1 to replace the dorman, and 2 new ones for my lights, plus a spare) and it came to like $10 including shipping. ebay was more than that for 1 switch.
I drilled a hole in the dash for the original Dorman switch and later enlarged it to fit the better one from Digikey. I don't have a photo of the new switch, but this gives you the idea. Same basic place, just a rectangular switch now.
View attachment 295852
Start searching based on the important things you need (SPST, on/off action would be the obvious big ones). Then I started getting pickier with enclosure ratings and looked only at stuff that was listed waterproof or IP66 or higher. You can select multiple entries in each column using the Control key, in case you weren't aware of it.
Roger - the switch you linked to on ebay is the same as the Dorman - avoid it.
Crazyal - the one you linked to on ebay is the either same one I got, or very very similar. Digikey was cheaper, and as noted, much easier to trust.