Hi. I'm a girl.
Really don't know a lot about mechanics. But I know I like driving my truck! However...
recently the curly q warm up light is not coming on after sitting in cold all night.

at first I didn't realize, so I did cold starts about 3-4 times... (the check engine light would immediately come on.) but generally started good.

once I realized that I should wait for the "DING" to start... I haven't had any problems starting at all. and check engine light went away.

BUT... Why isn't the curly q warm up light coming on?

 

my truck is the 2007 6.7 Cummins with factory installed exhaust brake.

 

I moved this to the deisel section for a quicker and more accurate response.
I'm pretty sure that the glow plugs heat up very quickly, within a few seconds and it would depend on how cold it is out for the light to stay illuminated longer or even at all.

 

For example... The truck was out all night in 25 degree F...
The next morning I got in the truck to start, turned the key over BUT NO GLOW PLUG indicator... So I started the engine. Engine didn't want to idle and check engine light came on immediately.


But now I get in the truck after it has set outside all night, and turn the key over, and wait for about 30 seconds and then start the engine. So that fixed the idling and check engine light problem...

What I am wanting to know is why isn't the glow plug indicator coming on? On it's own when it's cold outside?

 

Is your volt gauge dropping when you first turn the key on? You can usually hear the relay "click" on an off when the grid heater is cycling. It sounds like you may have a light bulb burned out in your dash.

 

Actually, your engine does not have glow plugs. It has an intake grid heater that turns on when the ambient temp is below about 55 degrees. Your 6.7 Cummins will actually start pretty well in cold weather even if the grid heater is not working. Like Brian suggests, it may be as simple as the bulb for the indicator light is burned out. When you first start your engine, do you see the needle of your volts gage dip a few times during the first minute or so? That is the grid heater cycling on and off. If you don't see the dip in voltage, then there is some kind of problem with the grid heater.