Got in this morning waited for the glows to go off and turned the key to start - click and completely dead dash. To be more specific everything on the interior harness was dead (my manual GP relay pulls its switch power from the distribution block on the drivers floor to the left of the brake pedal). Screwed around for awhile with the multimeter, cleaned the grounds, cleaned the battery terminals (I'm using top mount not the stupid side mount), getting 12.5V off of 2 optima red tops at the fuse block under the hood.

So I figured I was a victim of the dead ignition switch, so I blew $160 on one at advance auto parts (AC Delco brand). Hooked it up, dash was operating fine, figured that was the ticket. So when it's all done and I go to crank the engine over, I get the same as earlier in the day - click and dead dash. Cycle key off/on doesn't make a difference, dash is dead (as is everything on the interior harness). The only thing showing a sign of having power is the gear selector indicator under the speedo, it lights up orange...not sure why that's happening.

Could the starter have gotten fubar'd causing an internal short or something that drains everything?

I have no wiring diagrams, so I'm fairly limited in my ability to trace wires at this point...

Anyway, if someone wants a killer deal on my Tahoe, feel free to pm me...it's time for it to go

sounds kinda like when my pos cable from battery to starter went out..... you might wanna check that

Youve got a bad primary connection somewhere, either positive or negative. A bad connection can show 12.5 volts with no load, the shifter indicator probably only draws 100th of an amp, thus it works with the bad connection. If the problem was on a secondary circuit, some things would work normal & some wouldnt. Hope this helps.

I agree. Start looking at primary cables and connections. Work with the big cables; clean the battery terminals first.

Want to try something really stupid? Grab some booster cables, jump one battery to the other, and come back and tell us if anything changed... I know, I know, but humour me. I had a buddy do that the other day with his motorhome and vroom... segment the system then look for the bad spot.

I had a HUMVEE starter fail internally once and had this same problem.

If you have cleaned all your battery connections and the grounds to the block, well that leaves the fun one, the pos on the starter.

Uh-huh. And the cables... that was my buddy's problem. One of his cables had a crispy spot in it, about 1/2 way to the other battery... a slight bulge, and you could hear the crispy corrosion when we flexed the cable. Cur off the insulation, and it was all green in there.

New cable and vroom.

Uh-huh. And the cables... that was my buddy's problem. One of his cables had a crispy spot in it, about 1/2 way to the other battery... a slight bulge, and you could hear the crispy corrosion when we flexed the cable. Cur off the insulation, and it was all green in there.

New cable and vroom.

Yup. I have seen cables fail internally with no outward sign of trouble. Also, have had the cable ends loosten from the cable. And those post mount cable ends are famous for arcing and creating an open circuit under full starter load, even when they appear tight.

I yanked the starter out and had it tested at advanced auto, worked fine. So at least thats something I don't have to replace.

I'm up in PA for the rest of the week/weekend, but when I return to NC I'm gonna bring a plethora of battery cable/connectors with me and redo all those mo-fo'ing cables.

If it still doesn't start I'm going to have to light the bastard on fire...

Check all fuses? Check the alternator?

If he's got power (assuming 12.5 V), would the alternator be an issue for starting? Not being a wise guy, I honestly don't understand this electrical stuff very well at all!

Alternator is an issue because when alternator is bad, it won't charge the battery when engine run. So chances are after a shutdown, the charge at the battery is low. In this truck, the starter needs all the amps. to start. If you have good battery, then chances are you will be fine although the alternator is not charging fully. The electric comes from the reserve. However, it will probably last for once maybe twice after that the battery is too low to crank the starter.

Now, alternator will charge during the running of the engine to keep the electricity in the battery to run lights, ac, and anything that needs electric including LP, IP, Transmission, etc.

Don't ask me how I learn this. If I am incorrect, some other members can correct me.