The owners manual for my 06 SLT says that there's a "wait light" on the tach that looks like a coil that comes on and goes out before you start the engine. When I turn the key all the way over, there's no light. Is this temp sensor controlled so that it doesn't heat up above a certain outside air temp or something? Thanks, Shima

 

it is intake manifold temperature dependent. If it is over a certain point the wait light and intake grid heater does not function.

 

I only see my wait to start light come on in the winter. For the first 5 months I had the truck I'd wondered if it was broken.

 

You won't see it until it gets below about 45 degrees IIRC

 

Pretty much, they changed it for the 06's so it doesn't come on in the summer much.

 

on my 05's it comes on for less than a second if it is mild out.

 

I didn't see mine when I was living in San Diego until around Dec very very early in the morning. What was very odd was I drove to Nebraska that same month and even though it was below freezing my light didn't always come on?

 

The temp sensor is in the intake horn and if the air inside it is less than 59F (I think thats the number), then the wait to start light will come on while the grid heaters do their thing. Once the engine is hot and you turn it off, the air inside the intake horn will remain above 59F until the engine cools sufficiently. What this means is that once the engine is warm, even though you turn it off and the outside ambient air it is say, 32F for example, and you restart the truck, the wait to start light will not come on if the air temp inside the intake horn is still above 59F.

Make sense?

 

I understand that, I'm talking like leaving the truck overnight and waking up n the morning to go driving even. But when I got to San Diego like 2 months later it came back on... Not really sure?

 

Mine comes on from time-to-time in the morning here in sunny So-Cal.

 

Got me on that one, I'm not sure either.