Originally Posted by kerry

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.