I need a dimmer switch for my car. The orginal started to burn a little and melted some wires. What other cars have the same switch in them like the mustangs?
Assuming you're talking about a '91 Mustang ... I think your options are pretty limited. It's not like the older models with the pull-push switches that were practically universal.
Best options are to hunt Craigslist, eBay, and/or the local boneyards for one. You could probably score one for $5 to $10 ... unless you feel like coughing up a chunk o' change for a brand new one from someplace like 50resto.com.
Also, since you say your old one "burned up," make sure you clean the contacts of your connector(s) before hooking up the new switch. I went through this headache with the headlight switch of Frankenstang's '89 notch, thinking that it was the dimmer switch because there were no dash lights or exterior parking lights when you flipped on the switch, just the headlights, and the headlight switch was new; as it turned out, the original switch put some corrosion/gunk on the top-center connector and even with a new switch, it was acting all kinds of weird. Spray some electrical contact cleaner in there and/or scrape at the terminals with a metal pick or teeny-tiny screwdriver to clean that crap off there, if you see anything on the terminals except bare copper/aluminum.