Best place to go through the firewall on 2020 diesel

Time2gofishing1980 · February 6, 2020

I'm running the harness for a snow plow. I need to get the controller harness into the cab from the engine bay. It needs about 1"+ hole to get the molex plug through. The engine bay is tighter than a nun's ****. The underside of the dash on either the driver or passenger side is no better. Everything is jammed tight.

The best place I found is where the hood latch cable runs through the firewall. It runs through a small grommet. There's reasonable access to it and a little over an inch of open space on 3/4 the circumference. I was planning to push the grommet out and drill a 1/2" hole right next to it. Then connect the 2 hole with a file. I'd run the molex through and then fill it with strip caulk.

I would love a cleaner location with easier access but haven't come across anything. I even poked around with a Milwaukee inspection cam. Couldn't find anything easier.

I don't love the idea of running the cable across the engine bay. The cable runs from the battery side with is passenger side. The cable needs to run across the turbo area. I'm a little concerned about hear although I could wrap the cable.

Hoping someone might have a good suggestion for me. I'd prefer to have it enter on the passenger side to minimize heat damage risk.

ILSilverado · February 6, 2020

Sometimes you can go through the kick panel and thread up and around the wheel housing. Like the radio antenna area.

Edited February 6, 2020 by ILSilverado

mafd2 · February 6, 2020

We just installed upfitter switches on our 2020 Fire Dept. SSV Silverado. Here's where the instructions said to run cable through firewall. We just made a small slit in the rubber boot and it worked perfect. You can put a little sealant around the slit and cable. Here's a pic after install. Hope this helps.

Time2gofishing1980 · February 7, 2020

Is it a diesel? I don't recall seeing a boot that large and accessible in the engine bay. I'll look again tomorrow.

Perhaps I'll reach out to GMs outfitter team for advice if I don't have the same boot available.

mafd2 · February 7, 2020

1 hour ago, Time2gofishing1980 said:

Is it a diesel? I don't recall seeing a boot that large and accessible in the engine bay. I'll look again tomorrow.

Perhaps I'll reach out to GMs outfitter team for advice if I don't have the same boot available.

No it's a 5.3. Email Robert with GMupfitter. [email protected] or go to the website.

http://www.gmupfitter.com/