Never seen this one before. 98 Silverado 5.7 w/ towing, etc. Started last night and moved 3 ft ending in stall. Restarted fine, another 8 ft, stall. Getting irritated, i let it warm a little, and upon engaging drive, moved 35 more feet and hit the brake for a speed bump, and the entire truck shut down, lights, stereo, everything. It even reset the “check engine” (which is unrelated, some of the emmissions stuff) Restarted again after parking for a couple hours, and it did fine for 20+ miles, then the dash lights and stereo when out twice in 45 seconds. Today, it started and stopped 7 times trying to trigger the same effect with no luck…until…i pressed the brake again, and a full system failure occured again only this time the gauges went stupid and the truck will no longer start at all. Checked the fuses/relays, etc and all are good. Also checked battery terminals, loose connections, etc. Currently charging the battery to get it and the alternator tested. Anyone seen this before, or knows of something most likely to do this…I’m at a loss!
Are the battery terminals loaded with white corrosion? If so, tight is not enough. You need to disconnect and clean them.
look at the starter connections ,at the starter,all GMs run everything from that poor post,which lives in salt,mud ect ect,.look for SUPER corrosion.
WG
As mentioned check the big cable at the starter for tightness (very common to be loose) and the big ground (below the water pump) also known to become loose or never tightened.
Lets us know about any add on electrical equipment (alarms,electric brakes)
Did this vehicle suffer from a previously leaking Delco battery (at postive post)? cables may look good,but be the source of the problem.
There is a kit to get away from the problem of GM bussing at the starter solenoid terminal (good you pointed this out PO3,many people don’t know or can’t understand the problem this technique causes)
Yes they were, but that was one of the first things i checked and corrected…no joy
LOL…yep, they were tight, and minimal corrosion was present. Checked this second and still no joy.
The only add on is an amplifier for the sound system, and while this may not be so, i dont think it was the culprit since the system is only on and in use when my wife and kids arent with me. (Once a week at best)
I bought this truck nearly a year ago with the same Advanced Auto Titanium battery in it, but i know the front right was in a wreck by a previous owner (minor damage, but in the exact region of the battery). As far as the Delco, I dont know, but this is the same battery since i got the truck more than a year ago. This is also the first sign of trouble at all and all of this on the same night.
Did you peel back the red rubber cover from over the positive battery terminal connection? Try that, and if you find a white powder under that, replace the positive cable assembly.
Tester
Update:
Tested alternator and battery. Battery was bad, however, even with the new battery, it was very hard to start, and still dealing with significant performance loss (dimming lights, etc). Any other ideas, something I may have missed so far?
My main concern is that i had an engine light, which we all know can only be cleared by a code reader, or disconnect from main power, and the same for the stereo settings. Since there was no such code reader attached when this occured… LOL …this means that main power was severed at some point, but i am at a loss as to where else the issue may be 
BTW, this truck has over 206k miles. And thanks for the tip on the conversion kit…i may look into that if all else fails. Already $80 in the hole now…hehe, trying to keep cost down… LOL
Cant say that i did that…but if that is the case, wouldnt a cleaning be enough, or is there something i dont know about with that? I can say that there are multiple connections made on this one post (two from the factory, plus the amp supply), and that the two factory attachments do have that ring you mentioned.
Check the fusible links for signs of melting. These should be at the starter, where the battery cable attaches. There should be some small gauge wires that are the fusible links. Roll the last part of the wire with your fingers. If they feel rough, like partially melted, then they are bad and need to be replaced. These links feed to the fuse box.
For your year of truck the value of the conversion is not so great,for older trucks (espically with headers) the kits were of great value (the kit is essentaily a FORD starter relay and some cabling and a bridge bar for the starter)it reduced the 1 to 3 volts lost through various switches and connections (solved the dreaded “click” and no action on GM"s.
Just what was the failure in the battery? low CCA’s?
My mind tells me to start looking hard at the high amperage part of the electrical system,power feeds into the fuse box,maxi fuses,and we can’t ignore the ground side,when you say hard to start do you mean that the cranking speed is slow? you know what your truck sounds like when it is cranking normal.
We are dealing with a truck that has a full electrical shutdown that seems to be affected by pressing the brake pedal.
You may want to look into the bus point relocation kit,not as a exact fix but as a elimination of a area that we are unsure of. The company went by the initals M.A.D. located in Southern CA.Has the engine or trans ever been out? is it possible a ground is missing? look at the back of the passenger side head,sometimes there is a ground there.
Where did the installer source power for the amp? check this out. If I think of something I will post.
This is a possible answer. I’ll check it in the morning, but wouldnt a fusible link act like a fuse and either work, or blow out? I know the one at the battery post was in good shape, but beyond that, i didnt pay much attention to them. That is definatly a possibility, and worth the look since the fuses dont show any issues, but the power loss is obvious. Thanks BK!
Under that rubber cover are two ring terminals. The one for the starter is mounted first to the battery, and then the ring terminal for the power distribution center sits on top of the ring terminal for the starter. If corrosion forms between these two ring terminals, it can develope a voltage drop to the power distribution center. And when this happens, all sorts of weird electrical problems can develope.
If the corosion is heavy under this rubber cover, it’s probably migrated down into the cable where the ring terminals are crimped on. And strands of the copper cable are probably corroded.
Tester
Shew…that’s a lot to chew on 
My BIL would love to hear of a Ford part to fix my Chevy… LMAO! I definately dont wanna do that now!!! 
The exact failure is beyond me. We attached it to the test machine at the store, and it didnt even finish the entire test before showing only “bad battery” on the screen. Without load, it showed between 10 and 12 volts, and under load as low as six, but i had my back turned (the wife was with me, so I blame that on her…hehe) for the remainder of the test cycle.
The crank speed was low, and once the engine started to run alone, it was still hesitant, and eventually leveled to a low idle speed of roughly 600 rpm.
The brake pedal is what threw me for the loop. I dont see how a single switch could kill main power, even if it was a dead short in the line to the switch. I wont pretend to be an electrician though…hehe
Neither the engine or the tranny as far as i know, but i did have the tranny serviced (new fluid, filter, but not a rebuild) roughly 6 months ago. The mechanic said it looked good and that someone had a corvette shift kit installed into it. I took it in for a hard shift from first to second gear. He said that shift kit was the reason for that shift, and that it was a fast shift, not a hard one.
Ya lost me on the “passenger side head” thing. LOL, but the amp is supplied directly off the battery with a Walmart special install kit (again by the previous owner) and it is routed along the side walls into the doors wiring system (that is that it is fed through the same holes, not the wiring itself) into the cab, and then through the dash into the amp which is screwed down into the center of the front passenger compartment where it’s been since i got the truck. I wont say it’s impossible, but i dont see how the amp could be the problem.
Hmmmm… I’ll check this in the morning too… Thanks Tester!
In tricky situations, there isn’t a trick. Your power could be interrupted by a loose battery connection, in the battery. The metal could be loose where the cable connects. There could be no ground wire from the engine to the firewall / frame / fender. (Wherever they put it these days) The thing could have been left hanging after work was done on the engine. I had the lights go out on one of my cars, but never after the engine computer was changed, but I don’t know if the two were related. In any case, to prevent a fire, your negative battery cable should be changed. It’s the worst thing if electricity goes somewhere and has a hard time getting out because of a floating ground situation.
The best “clue” so far is how absolutely trashed your battery was. The passenger side head thing was,I wanted you to check and see if there was a ground strap at the rear of the passenger side head (you know,the cylinder head of the engine)
Fusible link wire is funny that way. If it was a massive short, it would burn out, and stop conducting. If it was a prolonged heating, just enough to get the wires to melt, but not burn through, they can become intermittent.
I had a friend whose car had a similar problem. We struggled for a month trying to figure it out until the starter gave us fits, and he went to replace it. Undoing the nut on the battery cable lug, and some of the smaller wires looked funny. When he started to mess with them, they fell apart in his hand. Replacing the link wire fixed the problem for good.
The wires to the alternator are hot (have 12+ volts). Their terminals must not touch the body of the alternator. The large wire is, usually, attached by a nut to the alternator. There is an electrically insulating washer /plastic piece on the large terminal. Be sure the plastic insulator is not cracked; nor, the large terminal touching/ near touching the alternator body.
Check the power wire to the amp where it goes through the hole in the fire-wall for cuts.