04 Suburban firewall pass thru

389sixpack · November 26, 2006

Hey guys, I pulled my snow plow off my old truck and have installed on my 2500 Suburban. Mechanical mount was easy, but I need to get the wire harnasses for the controls (5 wire braided harnass) and the light control (6 wire braided harnass) thru the firewall. I tried to snake thru by the drivers side fender wiring bulkhead, but failed to get thru. Now I hate to say this on this forum, but my ford has a big empty firewall gromet specifically for auxillary pass thru wiring. I don't see anything like this on my burban firewall.

So, what is the best place to drill a 3/4"-1" hole in the firewall - Or, is there some where I just haven't found yet?

Thanks in advance.

whmayhew · November 26, 2006

In the past I have taken a knife and cut a hole through the rubber where the steering shaft passes through the firewall. You have to go through two pieces of rubber. It might be easier to drill through from inside the cab, but never tried it. Evidently you are not using a Fisher plow as there is only on wiring cable that has to be passed through. It is only about 1/8 inch thick. That is only for the control of the plow functions. If it is a Fisher they changed the wiring in GM vehicles in 2003 and supposedly you can not use the wiring from 2002 on back. I have a 2004 plow on my 1999 GMC so you can go backwards. Good luck.

389sixpack · November 27, 2006

In the past I have taken a knife and cut a hole through the rubber where the steering shaft passes through the firewall. You have to go through two pieces of rubber. It might be easier to drill through from inside the cab, but never tried it. Evidently you are not using a Fisher plow as there is only on wiring cable that has to be passed through. It is only about 1/8 inch thick. That is only for the control of the plow functions. If it is a Fisher they changed the wiring in GM vehicles in 2003 and supposedly you can not use the wiring from 2002 on back. I have a 2004 plow on my 1999 GMC so you can go backwards. Good luck.

<{POST_SNAPBACK}>

Thanks. I'm installing an old Meyer (80's) plow but they are all still the same. Four wires for the solenoids. I'm pulling power and ground in cab. The head light and plow lights will be run next. I ordered a headlight module so I may be able to get away with 3 wires. I ran the control harnass thru the steering rubbers, as you recommended. I will probably pull lights thru the same. Sucks not having an access port on these. Thanks again.