Plug it in at night.

10 second delay is really short when it cold out The first thing i would do is set it to a minimum of 30 seconds. I know on the powerstrokes you can check the resistance in the glow plugs through the harness (the harness disconnects right at the valve covers) I'm not sure how the gm's are set up but that's a lot easier than pulling them. I did it once and replaced them all only to find out it was a bad relay, a really expensive relay after that.

I allways just use a test light to check glow plugs.disconnect lead,clip on pos.touch tip of glow plug with test light,if it lights you have a good plug.Glad you got it figured.

yea..plug it in over night.....

thanks for the info guys.did some checking my batt volts are 12.3. at hte glow plg i'm getting 11.3.is that enough?
also i have one bad plug but can't seem to get to the #8 to check it.so i may have 2 bad plugs.called the dealerand there is a $100 on the warrenty.they only replace the bad parts.if the relay is good it doesn't pay for 2 bad plugs.once again thanks for the info.

My remote start has a trigger wire that hooks up to the glow plug light. It waits until the light goes out and then turns over. I had to use the long crank time.

In the winter it usually blows white smoke and coughs for the first 15 seconds or so, then it starts running better. I never plug it in at night. I rarely use the truck in the winter.

Steve