Re: One last shot... Breaking up!
Ugh this should be fun! I need to read the service manuals some more and read through the suggestions on this page to get a better unerstanding of what, where, and how to test everything. I have a pretty good idea but I need a more in depth analysis on what to look for and how to test. I've been been testing grounds by testing OHMS of resistance, but I could do using votage as well. I need to read more into diagnosis of electrical systems.
Shouldn't be that bad
Fastest and easiest is test it for voltage drop. With truck running, set multimeter to DC volts.
Start at the battery B+, positive to the bolt, negative to the shell around the bolt (GM side mount connection)... wiggle the connection and look for voltage to show up... any voltage means there is resistance in the connection and you're reading voltage potential between the probes.
Then move to the next section to test... keep doing this till you get to wherever you want to stop... keep wiggling wires and connections (or better yet rev till the engine starts coughing) and look for the one length of wire that produces voltage... at this point you're probably looking at working between the back of the alternator and the power junction since the alternator is powering the truck.
If nothing shows up, then you need to disconnect battery and alternator and start testing resistance between all components.
That 16-19 volt issue is not normal.... probe from that junction block to different grounds to see where you get 16 and where you get 13.8.... I can't logically think of how this could not produce 16 volts in a lot of places - unless it's a high-frequency (low power) AC signal riding on the DC.... did you check for AC voltage where you found that 16-19 volts?
