HELP PLEASE - I'M IN OVER MY HEAD

I just got my truck safety inspected and on the road. I put in a new battery and all of the lights, wipers, etc were working at that time. Within the last week the "Genrator" idiot light came on (intermittently as driving). At the same time, all of my other electrical systems shut down. (no wipers, headlights, turn signals, flashers, parking lights, etc). Since the battery was just replaced I figured it must be the alternator.

I replaced the alternator today. I did it, "exactly" like this:
http://67-72chevytrucks.com/vboard/showthread.php?t=119379
(I used a rebuilt Alt from a 86 Chev 1500 for a 5.0L - Champion part# 019-4826-0, 92 Amp I think)

It currently will start, run and the idiot light is now off (for now while parked anyway), however, none of the other electrical systems work AT ALL! (Just like before - no wipers, headlights, turn signals, flashers, parking lights, etc - just as before) :whine:

I know nothing about automotive electrical. Was wondering if someone who's has had experience in this area could maybe steer me in the right direction?

Please remember I'm not the sharpest knife in the drawer:crazy: so please use lamans terms, pictures if you have them. If you could do your reply in Crayon that might help too...:lol:

Check the main wire out of the alternator, where it connects to a junction block on the inside of the fender. Corrosion there, or further on towards the regulator cn cuse your symptoms, as will corrosion at the battery cables.

Replaced the battery cables today. Wasn't that, same problem still.

Will try the alternator wire and the junction block over the weekend.

This has been an interesting thread for me as I have been thinking about it all day. After looking at the wiring diagram and racking my noodle I decided that your problem is that you aren't feeding voltage to the fuse panel or you do not have a good ground from the cab back to the battery negative.
The battery cables were ok because the truck was starting. the junction block wire (red) is ok because it feeds the key switch and the truck started. I don't know what you've done as far as wiring on the alternator swap but it shouldn't affect the fuse panel. Now there is a junction of three red wires one of which goes to the firewall block and one to the key switch and one to the voltage regulator. I wish I could say where the junction is but I can't tell from the diagram and I don't have them on my truck in the engine bay anyhow so they must be under the dash. .What clued me to the fuse panel was the statement you made that your lights didn't work and most of the other things didn't either. You either don't have a 12 volt feed to the fuse panel or you dont have a ground connection from the battery negative to the frame. the headlights work with the key on or off so that's what suggested the fuse panel or a no ground issue.
What I would do is check for voltage at the fuse panel with a multimeter and follow the red wires from the junction block and check all the wires that tie into it. If you have the negative battery cable connected to the alternator mounting bracket then see if there are any ground straps from the engine to the cab and frame. There should be a black wire mounted on the radiator support that grounds the headlights. Run a jumper to that from the negative battery cable and see if the lights come on. Don't forget to turn the switch on LOL. Try these things and post back. The wiring diagrams are located in the sticky thread on the top of this page. If you have a zoom feature in your viewer it will make them easier to read.

Ok, I got out the wiring diagrams after work today and started poking around. I looked at the juction block as suggested and I only have the wires labled 12R (Red) and 16B (Black) in the juction block.:confused: (Maybe becuase it's a 6 cyl and not an 8 cyl as the wiring diagram refers to?)

According to the diagram there should be a 18B (Black) in there too. Since it was missing I started seaching high and low for it. During my search, and sitting on the frame, I found a detached and heavily corroded grounding wire. I looked above it and on the firewall was just a "O" ring electrical connector with nothing attached to it. I attached one end to the firewall and the other to an engine bolt. Fired it up and BINGO!! :metal: Everything works except the turn signals. The 4 way flashers work so I figure that it must just be the turn signal module plug-in on the fuse pannel inside the truck. (I'll replace that)

You know, I just want to thank you guys for your help. You were bang on! I'm so happy I found this web site. What a great group of guys. Thanks again.

Ps: I think I'll replace all the ground straps. I see I can order a kit from GMCPauls for $27.95. Link: http://www.gmcpauls.com/Electrical.htm

Rick