Glow plug light not illuminating

[firemandan774]

I just replaced the timer relay for the fuel shut off solenoid . Prior to changing this part the glow plug light would illuminate and then go off . Today it didn’t illuminate and it took a bit to start. I’m thinking glow plugs are not heating. Shutoff solenoid is now functioning as it should but appears the glow plugs are not now. Any ideas

 

[firemandan774]

Sorry buddy he machine is a Dk55

 

[Roadworthy]

I'd start by putting a volt meter on the glow plugs to see if they're getting voltage and how much.