02 Tahoe 5.3 LTE electrical problem.

[Chris11]

My Tahoe is doing some weird things. I had an issue prior with it not starting; time passed before had chance get back to it and battery needed a charge. Battery was charged full and I tried to see if was BCM and pass key issue.
When it did not start before, there was no response when to trying to crank but all dials were functional (as were fobs, lights etc). This time, attempting to try the pass key relearn, when turned key there was absolutely no response, no dash lights even; I could not turn on interior lights, basically no power as would be case with dead/no battery. I cursed, turned ignition off and pulled key out. After doing that the speedometer, volt, rmp, gas, oil press gauges all went wonky, going from off to position to full/redline position, back down then up again, finally back to 'off. So I put key back in, no dials, no power but a small humming noise. And that's that, I cursed a couple more times and enjoyed the rest of the day instead.
Can anybody shed any light on this issue for me? Please, and thank you in advance.

 

[shoplizard]

Hi. If you're positive that your battery is fully charged and voltage is at least 12.5 volts, then I would suspect a loose, corroded or broken electrical connection. I found that on some of the early 2000 Tahoes Etc. there is a ground wire at the rear of the engine mounted to the block that will sometimes break inside the insulation and cause some or all the problems you are experiencing. Sometimes a mild tug on the ground wire will reveal if the wire itself is broken. If that is not the cause, I would suggest removing the battery cables from the battery and thoroughly cleaning and reinstalling then. Check all other grounds for corrosion and being properly secured.

Good Luck, Shoplizard