How do I reinstall an operating thermostat on dryer without the wires being marked.?

I took out the old thermostat, it has 4 wires. One is red, one is red with a white stripe, and the other 2 are purple. I forgot to mark the wires and now I'm not sure how to hook it up safely.How do I reinstall an operating thermostat on dryer without the wires being marked.?there maybe a wiring diagram inside the dryer behind the top panel...you could always call the manufacturer and ask for tech support ... give them the model # of the machine they will walk you thru it