Author Topic: 79 K10 FIREWALL FIRE /grommet info (Read 5108 times)

danmandan · « **on:** April 20, 2020, 10:19:24 AM »

Hi I've got a 79 k10 that looks like at one time it had a fire in the engine compartment on the passenger side on the firewall ,, there's a grommet there that looks to be about 2" in diameter that comes through from the cab,,,it looks like it has 2 half inch or so holes in it ,one left hole has wires coming out of it ,, most look to be to the ac and heater fan relays etc ,,the other hole to the right is enpty ,,it looks like it had been burned and most of the wires there are not shielded and have been spliced,, would any one have a pic that would show the wires that are on the firewall that feed the ac and fan motor ,relays there ? And what if anything was in the other hole in that grommet,, 1979 chevy k10 with 350 automatic trans and air conditioning Thanks for your time,, been sitting awhile and trying to bring it back

VileZambonie · « **Reply #1 on:** April 20, 2020, 05:34:34 PM »

Can you post pics?

This is a 79 K10 firewall

danmandan · « **Reply #2 on:** April 21, 2020, 09:12:32 AM »

Hi,, Thanks for the pics and your time ,, The picture you posted is the grommet I'm wondering about ,, I will take a picture of mine in a little while and post ,, the grommet looks to have wires on the left and a vacuum line on the right ,, mine doesn't have the vacuum line there the hole is empty. The other picture of the" junction block ?" I see that my wires have been messed with there too ,,I found a wire nut there ,,going to have to look at that too .. Ill post pics soon and thanks again,, Dan

danmandan · « **Reply #3 on:** April 21, 2020, 12:45:30 PM »

Hi,, Here are some pics of what I've got going on,, on the junction block I see there is part of an old wire still there ,burned off? the wire nut was kinda hidden behind the brake booster attachment,, going to trace where the wires are going from there,,, the wires from and near the grommet are all askew and I don't know if they are correct,, looks like the vacuum line is missing,,trying to clean up under the hood, heater/A-C fan doesn't work,, wont power on ,, the heater controls don't work,, I think that it cant change from floor to panel etc. is because the vacuum isn't hooked up ,,Maybe that's the vacuum line on your truck that goes through that grommet into your cab,, that's gone in mine

VileZambonie · « **Reply #4 on:** April 23, 2020, 02:25:12 PM »

The passenger side grommet should have the HVAC wiring harness and vacuum hose that connects to the vacuum reservoir. The junction block should have a fusible link there. I hate to say to look at the pic I posted since that one is a clumsy repair someone did as well but not nearly as bad as using a wire nut. See the attached pics for reference

VileZambonie · « **Reply #5 on:** April 23, 2020, 02:34:55 PM »

danmandan · « **Reply #6 on:** April 25, 2020, 08:01:50 AM »

Hi,Thank you for the help ,,the diagrams you've posted have alot of info that I didn't know,, The wire nut is taking place of the fusible link that burned up I guess ,did some digging and found that there is supposed to be a 16 gauge fusible link there,, going to have to fix that,, traced the wires down to the starter and those wires look suspicious too,, think the truck is supposed to have 3 fusible links ,, one at the junction block a 16 gauge and 2 by the starter ,, a 14 and 16 gauge , Looks as if one of them is gone by the starter ,,and the other is frayed,, scary ,,I will post a couple pics today ,, and thanks again for helping, Dan

danmandan · « **Reply #7 on:** April 25, 2020, 03:37:03 PM »

Here are the pictures of the starter wires ,, The picture of the wire with the blue connector that goes to the splice looks about ready to come apart at the splice,,is that one of the links? The other wire looks like it had 2 wires coming off of one lug before and it goes to the other link,, Any info on this? It looks like someone has been just using quick fixes for this truck till now