Last night about 10:30 we were moving stuff out of the garage at the old place to the new one. Going back to get another load, just started to pull into the driveway, and my '77 M880 died. Engine died, headlights out, entire electrical system shut down COMPLETELY and suddenly. I've had no electrical trouble with this truck at all; put a new battery in it when I got it, and an alternator because the bearings started howling (not really an electrical problem). We drug it out of the street and into the driveway with a Ford. Only thing I could think of at that time was broken terminal connection inside the battery, so we put the jumper cables on it. Nothing. Another guy checked the primary fusible link - good. I closed the lid, and didn't mess with it anymore because of the time; we loaded the other truck, took it back and emptied it, and called it a night.

Any suggestions about where to start on this one?

Check to see if you have voltage to your fuse box.. If you do not have voltage to the fuse box the pull your dash apart and check to see if you have voltage to both sides of the amp gauge... The amp gauge is the first place the fusible link goes..Did you verify that you have voltage on both sides of the fusible link?? After power passes thoug the amp gauge it connects to four other wires that send power to the ignition switch,headlamp switch,fusebox,and the alternator.. If you have power to one side of the amp gauge and not the other then it has burnt and needs replaced.. If you do not have power to either side then you need to recheck the fusible link.. By the way just because the link doesn't look bad dont mean it isn't burnt..I chased an electrical problem on my 86 dodge for a week before I found the burnt fusible link.. To verify that it is good pull on it if it stretches then it is bad.. If it is good it should not stretch...

We checked the first link by jumpering around it. ;) Thanks for the amp gauge lead; that's where I need to go next. It was late, we were all dead tired, and just didn't feel like messing with it much last night. First thing this evening I'll get the test light and start at that link again and follow it out.

Sounds like you nailed it with the ammeter, though - and that was just what I was asking. I'll let you know what I find. Thanks again! :)

yeah, I just bypassed my am meter by putting a bolt through it.. though, I later found out that i had a robelm with it grounding out through the electrical tape because of the high amps. I solved the problem by putting the whole end part, with bolt, inside a piece of plastic pipe, with a cap at one end, and heavly wrapped it in electrical tape.. worked good. I think it is such a dumb idea how they hooked it up, but oh well.. just gotta live with it.

Garrett

and the problem is definitely the ammeter. Of course I disturbed it pulling the dash, so it immediately checked out OK - and everything worked then, too. By wiggling the black wire I could make it come and go at will. Thanks a lot, man. You probably know how much time you saved me. :)

I just try to help when I can glad it was easy