92 K2500 Revival

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Komet

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Well I've really done it this time. A friend of mine bought this truck as a drivable project with a Cummins swap, because he wanted the engine for his Vortec 350 / 4L60e Suburban. I told him I wanted the parts he didn't, so fast forward to today and it's on my property sans engine. It's had some very hacky mods done to it and I'm in the process of unpimping the electrical system to hopefully have a prepped chassis to receive the 350 when he gets around to pulling it.

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Things get really good under the hood:
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But the lights already work, so that's good!
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I have some unconventional plans for this truck. Here's a sneak peek of what's on my workbench. And by workbench, I mean plastic foldy table:
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I'm thinking I need to clean up the engine bay soon. That old Cummins was greasier than a county fair concessions stand and I ain't kiddin ya.

Oh, I'm also in the market for any and all Forest Service GMT400 reference photos, documentation, anything related so post up what you got. Thanks!
 

Komet

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Looks like a good project, doing a build thread?
better get rid of that C on the fender :)
Yeah I thought I'd post here with updates. The C has been removed from both sides.

Made great progress today, brought power over to the junction block on the driver's side and gained what appears to be full power to the fuse box. Power windows and locks are working, radio is working, door open chime is working, gauges move around. Guess that means the ignition switch is working. Now I have a list of stuff that doesn't work:

-HVAC controller, not lit up, no function.
-Wipers
-Equalizer screen on cassette player.
-Running lights / turn signals

I got a connector hanging below the dash that fits a GM turn signal flasher so I think that got pulled out during the unpimping. Didn't take any pictures today so I'll end my update with my professional bodywork enhancement:
Before:
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After:
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Komet

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Well fellers, the wins just keep coming. I put the 'ol razzle dazzle (brass brush, random wad of sandpaper, excessive qd electronic cleaner) on the contacts going to the digical hvac machine and she came right back around:
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We got all three fan modes, we got blend doors blendalating, we even got power to the equalizer screen and I'll be dipped, the tape deck works.

Interestingly, the hvac controller is getting constant 12v. I can turn it on with the key out and the screen is always lit. My buddy told me to try hitting the bonus switch under the dash, but it's already gone. So there's one weirdness with this circuit where it needs to be corrected to switched 12v but that's not too bad.

I think the hazard flasher has somehow escaped from the vehicle; I couldn't find it under the dash and there's a convenient empty clip where it looks like it should be. I jumped the loose connector there and all four marker lights lit up so I'm pretty sure I'll have turn signals after I acquire a flasher. Also took a video on my phone and confirmed brake lights work. I think I'm down to just wipers and the switched 12v issue?
 

Dropped88

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Well fellers, the wins just keep coming. I put the 'ol razzle dazzle (brass brush, random wad of sandpaper, excessive qd electronic cleaner) on the contacts going to the digical hvac machine and she came right back around:
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We got all three fan modes, we got blend doors blendalating, we even got power to the equalizer screen and I'll be dipped, the tape deck works.

Interestingly, the hvac controller is getting constant 12v. I can turn it on with the key out and the screen is always lit. My buddy told me to try hitting the bonus switch under the dash, but it's already gone. So there's one weirdness with this circuit where it needs to be corrected to switched 12v but that's not too bad.

I think the hazard flasher has somehow escaped from the vehicle; I couldn't find it under the dash and there's a convenient empty clip where it looks like it should be. I jumped the loose connector there and all four marker lights lit up so I'm pretty sure I'll have turn signals after I acquire a flasher. Also took a video on my phone and confirmed brake lights work. I think I'm down to just wipers and the switched 12v issue?
I see someone is also a VGG fan
 

Komet

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Got a little bit further today. Probed the wires going to the wiper and all of them had some form of voltage on them. Had a feeling that black one was supposed to be a ground, and it was. Grounded that and got a click out of the wiper but no action.

Had a look at the circuit board, the contacts that ride on the circular thingy were heavily worn but the solder didn't appear to be cracked or otherwise inoperable. When I request a single wipe I get a click followed by another click so it seems like the circuit board might be ok but the motor is shot. I can't manually move the wipers.

The connector was cut and reattached in expert fashion at some point:

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Yeah that's electrical tape over some folded wires. I amended the situation:

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I found "the switch" my buddy was referencing:

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There's only one big ol lopped off red wire like that, so it was being used to shut off power to the fusebox (like directly to battery full current fire hazard level 9), perhaps to solve the excessive draw from the hvac always being on. Correcting the wiper ground fixed that by the way, it shuts off with the key off as expected now. I also got reasonable readings for the fuel meter (yay I have a half tank of diesel to deal with) and voltmeter so I think we're really close to electrical nightmare mitigation.
 

Komet

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Continuing to clean up the hackery and identify what goes where. I only have a few unidentified wires left on the driver's side. I've actually pruned back a bit further than these photos now but you can see the progress:
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The wire delete pile is getting pretty substantial (keep in mind, none of these contributed to anything currently operational on the chassis):

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I pulled the wiper motor, accidentally broke an edge off the cowl, got hung up on the hood hinge or something while I was looking at the other end, but that's easy enough to score at the yard. Motor clicks but can't spin itself with no load, going to replace the whole unit and see if that works. I suspect the gears are busted internally, wiper linkage moved quite freely in the truck.

Was talking with my buddy about the truck, it's got no front diff and gutted CVs to prevent the front wheels from falling off again. It's got a 3.42 13 bolt (one bolt sheared off) out of a 2wd truck. Does have the G80 though so we're gonna need to test on that in the future. He cut the ebrake cables, so I'm gonna need those too.

Amp draw at the battery is only 0.065 though, that's pretty good.
 
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