the 5th tab is most likely the light.
the two center tabs are your common
Nothing special about carling switches. however you can order your exact switch
Carling Technologies offers a wide variety of electromechanical switches and electronic controls suitable for numerous applications.
www.carlingtech.com
I usually order from waytek. you have to order the switch and actuator separate (there are multiple series of carling switches)
Rocker Switches from Waytek come in many versions including marine rocker switches or automotive rocker switches. Illuminated, SPST, On-Off styles and many more are available for bulk orders.
www.waytekwire.com
you can also pull the switch apart and clean the contacts
pull the switch from the dash
turn upside down
with small screw driver, unsnap the terminal block from the switch body
keep upside down (so you dont loose the springs and bits)
clean contacts with 180 grit
put everything back together