see photo where is fuse?
 

Regarding my 1991 350 SD, I took the cover off my GP relay expecting the fuse to be obvious, between two screws, right? Here is the photo of my GP relay. Does this version have some other type of fuse? Is it inside the relay? Any assistance appreciated.
JT

You have the later style glow plug relay with a built in auto reseting circuit breaker. There is no fuse on that version.

What fault are you chasing?

Thank you Alex. I had been reading a lot on this forum about testing glow plugs so when I pulled the top off of the relay to test the GPs I expected to see a fuse and when I didn't I wondered why. I found my 4th and 5th glow GP were bad and replaced them today. Everything is fine now! Thank you for the information.
JT