Jsdirt

Heat shrink butt connectors are my method of fixing this kind of damage up here in MA, where the salt flies every winter, and moisture is a constant concern 365 days a year. Some people argue soldering is better, using heat shrink and waterproof shrink-tubing on the solder joints, but solder cracks with vibration. Up here, we get constant and relentless vibration not just from the normal operating characteristics of a motor vehicle, but our legendarily shitty, 3rd-world-country-rivaling road conditions, so heat shrink butt connectors, crimped properly, will be much better than soldering. The key is to make sure you get EVERY wire back to its other half. Should be easy when cut in the middle like that, since all the wires should be the same color. At connectors it gets tricky, since sometimes automakers like to change wire colors after a connection point. In a situation like you have here, I'll cut all the wires diagonally, so that you don't end up with a giant mass of butt connections all in one spot. Makes the repair much neater. If you can't spare the wire length, then don't worry about this - as long as it works, all is well.

Also make sure the fuel in the tank is decent, and not ethanol-separated or stale. I'd wager that thing sat around a bit and it's probably borderline. Change the fuel filter, then once you get a few full tanks of fuel through it, add some BG44K to the 4th tank at the gas station before you fill up. That'll clean everything out. Might take another 4 or more tanks after that before it starts running normally again.

Flat lined means either the sensor is completely dead, or wiring shorted, or blown fuse. As I said, betting on a shorted wire. Power Probe will easily find that. Power on one side, signal (lower varying voltage) on the other. If you've got no power, that'll flatline it too. That's fused power, labeled as such (usually). Test light will work for testing the heater circuit (the 2 wires of the same color) - it's a pulse-width modulated (PWM) circuit, so you should see blinking / flickering of varying speed if that circuit is working. You'd have a code for that, though - your code is for the sensor wiring, not the heater circuit wiring, so I wouldn't worry about that yet.

Your answer is right there in the code description. "CIRCUIT MALFUNCTION" - that's not a mechanical problem - it's a circuit problem. You need to check the wiring from the plug to the ECM for a short.

It was running - no reason to replace anything ignition-related. You either need to do a hard reset (disconnect battery for an hour or more, then touch the positive and negative wires together [away from the battery, of course], then reconnect both to the battery), or you need a new battery (voltage too low). If the jump pack somehow put out more than 15v, you could've fried a module or 2 as well. Usually sudden problem like this are due to logic lock (need to get the STUPID out of the computer by doing the aforementioned hard reset), loose / corroded battery cables, or low battery voltage. If the battery was removed at any point my money would be on something related to the cables.

Yep, great point. I've seen plenty mix-matched in my time turning wrenches, but ideally you'd want them all the same brand. Sizing is the most important, with a matching brand second.

As others have already mentioned, ANY vehicle equipped with a transfer case MUST have 4 matching tire sizes.

Yep, well aware of that. Like I always say, electronics are great for desktop computers and smartphones. They have no business in an automobile, IMHO. Part of the reason I just quit the auto industry for good just 3 weeks ago. Sick of the infuriating engineering, endless costs for tooling and constant updates, rust from the shitty, low-bidder chinese metals they use, and complexity that makes pattern failures a thing of the past when it comes to vehicle electronics. I was mostly working on '04-'18 as of late - I can only imagine what demons are in store for the '22-up models. Glad I'm not a new young tech starting out with this bullshit. Took on a new job as a maintenance tech for a giant corporation in the city. Never been so happy to go to work in my life, lol.

GM screwed up the system. Shocker, lol. Not surprised one bit! Thanks for the info.

He may have a tough time doing that if this is in a '74 Vega ...

So, the 6.0 is out of a '00 Sierra 1500. What was it put into?

That's horseshit. The dealer is LYING. I've run a Dively flatbed with LED lights from the factory since 2009 with my 2007 Silverado. There's always the possibility that GM screwed with the system and made it suck on the newer models, but I can't see any logical reason why low-current LEDs would cause zero output from the trailer plug. Sounds like yet another GM dealer attempt at weaseling out of the warranty. If they won't fix it, take it to another dealer that will, or call GM corporate and tell them you are NOT happy.

Should be right up on top of the fuel pump assembly.

Volt meter is usually hooked directly to the battery, or wiring headed that way. At least that's the way I prefer it, so I'm sure the battery is actually being charged by the alternator no matter what load is being put on it. I prefer to keep the 12v HEI wiring by itself to avoid any ignition problems.

Temp is just as easy. 1 wire - done. It grounds through the sender, like the oil pressure sender does. Power goes into the gauge in the cluster, then grounds through either sender. If it were me, I'd just install a rack of Autometer gauges, or install them in the cluster. Super simple hookup on those. Oil pressure can either come in mechanically through a tube, or electrically through a sender (also 1 wire). Same with the temp (no tube, though - electric only).