Oil pressure gauge reading zero

[chim666]

Not had any problems before (i.e. no fluctuating readings) but got nothing today when I started it up.
I found that the sender connector was a little loose, so I crimped on a new connector, but still nothing.
I earthed the connector wire against the body of the sender to see if it hit the max reading, but it was still at zero.
I noticed that there was what appears to be an in-line fuse holder on the sensor wire (about four inches from the connector and strapped to the chassis tube). I can't see any reference to a fuse in the bible or on this forum - any ideas?

ETA - I've just checked the volts at the connector wire with ign on: 6.5v DC.

Edited by chim666 on Monday 2nd June 13:18

[chim666]

Well, I don't know what I've done, but after a bit of wire-wiggling then stopping to have a bit of lunch, I tried it again and it's ok now!
I'd still like to know what the 'in-line' thing is though.