Loose negative battery wire

[postoak]

Give me a little heads up on what to expect when I take a look at the wire that comes off the negative terminal of the battery and runs up under the air intake. What does it connect to? Is it easy to get to in order to see if it is tight?

 

[Tex99Tahoe]

Mine's a `99, just refreshed all the grounds. The main ground line went to a stud on the lower front of the engine. Easily accessed from under the truck. Found the clamping nut just finger tight, not good. Cleaned all that up and snugged it down good, hopefully headed-off a future catastrophy...

 

[postoak]

On my 2008, the larger wire goes to the front of the engine, on the top. Very easy to check, and it is tight. But the smaller wire that heads up under the air intake is the problem.

 

[Tex99Tahoe]

On mine, the smaller wire goes right over to the fender sheetmetal by the battery, so it had a good tie-in to engine ground and body ground. Yours, going under the intake, is a mystery to me.

Things like this are why I've always acquired the factory manuals, but mine only covers `99...

 

[postoak]

I traced this wire (which is about 1/8" in diameter) further. It goes down to the passenger side frame rail, then under the lower radiator hose, and then straight forward and under a metal support. That's as far as I can see. Anyone have any ideas? What's this wire for?