Just broke down yesterday. Tahoe acted like the fuel pump went out and came to a rolling halt. Put on 4 ways, called AAA for a tow. Within that time I lost all electrical as well to the truck. No dash, radio, windows, etc. Only thing that worked was the aux power ports (cel phone plug ins/cig lighter)
Got it towed to brothers shop. Switched battery.. Had power to everything.. went to start truck, not even a click.
Went in to get him so we could push it into the shop. Went back out to put into neutral, and no power whatsoever to anything. Only a blinking yellow light on the radio.
we checked the wires, load tested both batteries, checked fuses (underwood starter no power, rest power)
can't even connect the diagnostic computer to the truck..tracts like there is nothing there.
Only symptoms prior to this was traction control randomly kicking in fro a stop, and just prior to dieing on road the is instruments on rear view mirror started to blinking off and on
bad ECM?.

 

I think the first thing to check would be electrical part of the ignition switch. Is positive voltage getting to this switch? If not, trace backwards. Could be fusible link, fuse, but needs to be troubleshot.

 

But would that cause no power to the headlights, door locks, horn?

 

Yes, it would on my 1971 Volkswagen !!!! Wait a minute - my 1971 VW does not have power locks....has the technology changed since 1971????

 

Thanks for the reply. Heard mixed reviews about the previous question, so thought I'd double check.
And yes technology has changed.....everything is now powered by Skynet (AKA Google).

What happened to the good ole days when all you needed was a shop rag, can of ether, and a screwdriver to start a dead car.

 

UPDATE

May have found the culprit. Fuel pump is out and blew fuses to the control modules.