Hello everyone -

I have an 03 Sierra 2500 HD and am geeting ready to add some guages.

Does anyone know if there is a hole in the firewall that I can use to run pyro and boost wires/tubes thru?

I would prefer not to drill if I can avoid it.

Hello everyone -

I have an 03 Sierra 2500 HD and am geeting ready to add some guages.

Does anyone know if there is a hole in the firewall that I can use to run pyro and boost wires/tubes thru?

I would prefer not to drill if I can avoid it.

Yes you can go through a factory gromet above the brake petal on the firewall

I think most of use went through existing gromets. I went through the main wire harness gromet. I just made a little cut in it with a razor blade.

You can carefully unwrap the electrical tape from the factory harness on both sides of the factory grommet. I find it easier to poke a solid wire through first to use to pull the wires you want. Then wrap itr back up to make sure no water gets in. I have an extra power wire from stud 2 now and my tonneau lamp wiring pulled through.

You'll save a lot of time and headache if you just pop a hole in the firewall. There is a nice flat space just to the right of the turbo (looking from the front). You can see this spot from the inside right above the accelerator pedal. A lot easier than dealing with the existing grommet and worrying about poking the factory harness.