I noticed some wires under the dash that have a label on them, something like customer access IIRC. Then there are some wires under the hood on the driver's side that appear to be the same color combos. I tried to search last night and this morning but haven't found anything. I read the owner's manual and no luck there. What I need is a hot wire and a hot in run to power the heat function on the seats I purchased and was curious if any of these would work? It got late and dark last night so I didn't test any of them, but still curious of their purpose. Why are they there? I know I've seen something about them on here but I just can't find it now.
Thanks all

 

They are there to save you a little time and not have to drill a hole in the firewall to run your own wires for any accessories. Look right behind your power dist box and there will be a few wires with shrink wrap on the ends. They are pretty good sized wires and I use mine for my GP LED and a few other things. I have a 12v constant running through one as well, fused of course, and its fine. I dont know how thick a gauge you need to run a heater though...

 

Those wires are "pass through" wires.

They allow connecting accessories out side the cab,w/ out running wires.

The ones on the driver side under the dash,connect to the ones on the fire wall under the hood.

Probably not what you're looking for to do the seats.

 

I've used them for my tranny temp sensor lead, water temp sensor lead and my GPR LED. Not sure if they are big enough gauge for heated seats. I didn't wire my amp using them, that's for sure.

 

on my '00 they were originally labeled "customer use for aftermarket equipment". The manual I had somewhere used to state they were for the trailer brake hook-up since you'll notice that the colors relate to blue brake, red +12. black ground, and whatever white is. they also end about where most people put the brake controller. Otherwise they are just 22 ga wires that go through a bulkhead connector and are sealed to the elements like everybody else said.

 

Thanks for the info. I guess I could use the positive for the continuous power lead. I just need to trace it and see if/where it connects for power.