[Vwdiesel] Caddy glow plug light acting up

[Doug]

What is the Caddy trying to tell me? Last week, when we had the below 
zero weather, I drove the truck to work and then had a panic attack when 
I went to go home and the glow plug failed to light when I turned the 
key. I turned it off and back on and the light came on normally and the 
engine started. The next day, in the garage in the morning, the glow 
plug light came on but was dim. I turned it off and back on and the glow 
plug light lit normally and I drove the Caddy to work. When I went to 
leave, I had the same scenario. Today, I went to put the Caddy in the 
garage for the night and it took two trys of no light and then it lit 
and the engine started normally.
Is this an indication of a faulty relay under the dash? If not the 
relay, what is the Caddy trying to tell me?