Thank you for choosing Aerospace-Aviation360 for Part Number 5916817 described as Electric Thermal Switch Line Test Set. Check The Five Thermal Switches, Sensors & Associated Wiring. Use -501 For Dc-9 S With Three Thermal Switches. by Mcdonnell Douglas. This is an ASAP Semiconductor owned and operated website. We are a leading supplier of aircraft tooling parts. You have 24/7 x 365 access to our diverse product database with the fastest lead times in the industry.