1991 Sierra Dimmer switch

I have a 1991 Sierra and am trying to locate a new dimmer switch. But, the dimmer switches available at local auto parts stores do not look anything like the switch that is currently on my vehicle... Has anyone ever came across this before? And if so, could you please point me in the right direction. The dimmer switch that is on my vehicle looks to to be a Headlamp/Dimmer switch combination... If that helps?

Thanks Again for your help!