Can't tell for sure but something looks disconnected in our throttle linkage in that photo. The relay compares the draw on the first plug with the draw on the rest and if there's a fault the glow plug light wont work or will flash. But if all the plugs go out the relay detects no difference between the plugs. Also there's a strip fuse in the system which might have failed.
Check that you have 12 volts to the plugs with the switch in the glow position, If you do, then unplug the glow plug harness at the relay and test the resistance on each plug. Should be less than 1.5 ohms or so.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13