Help! Sudden electrical problem

[Farmstore34]

Hey all'
I went to use my '72 k20 today, it has been working great, and stopped to throw some stuff in the back. When I got back in, I turned the key and there was nothing. I checked around, I had no lights, hazards, heater, radio, NOTHING. I tried roll-starting with no luck, then went and got another rig and jumper cables. Again, nothing. I towed it home, got my elec tester out, and the battery is fully charged. I have power down to the starter solenoid, but no power coming out of the solenoid on the other terminals. Would a bad starter/solenoid cause a no power condition on the rest of the system? I've haven't had any electrical problems since I got it a year ago. Thanks in advance,
Colby.
P.S. it has a 350 motor and 4-speed.

[JimKshortstep4x4]

Did you check for power on the main feed wire to the cab?

It is a red #10 wire that goes from the terminal on the right fender across the radiator support and in the harness to the cab through the bulkhead connector.
The wire has a fusible link in it which may have gone bad or there is a bad connection somewhere along the way.

It is also possible for the battery connections to be be making partial connection, (enough to make your meter read but not enough of a connection to power up anything).

Jim

[cdowns]

a poor rusted up neglected ground wire will cause no juice to flo it is after all a two wire system

[67mater]

Speaking of grounds, my abttery grounds to one of the water pump bolts; is this normal? The cable and its ends look original.

[hvychve]

I agree with Jim,,, check your main supply to cab, usually runs to that little black junction, and can have either fusible link wire or fuse (stock is a fuse,) and runs in that plastic cover along the radiator support.
always follow from source up, to dertermine loss of power.

[VetteVet]

Start at the source, the battery cables, tight clean connections then the negative ground and the positive at the starter. BTW the positive ends at the starter no power will show at the solenoid until the key is turned to the start position.All positive power comes from the red wire stated above. The red wire feeds the key switch and the light switch, the horn relay and then the key switch feeds the fuse panel and the starter solenoid.

Speaking of grounds, my abttery grounds to one of the water pump bolts; is this normal? The cable and its ends look original.

The negative battery cable can be bolted to any good ground point on the engine, but remember, the engine is rubber mounted so it needs to be grounded to the cab and the frame to complete the electrical circuits. IIRC there are 5 ground straps on our trucks to complete all circuits.

[bad68bowtie]

For what it's worth, I had a VERY similar problem just last week. Went to fire up the truck, nothing, and then just like you described absolutely couldn't get anything else on the truck to work. I thought something was shorting out the truck but I couldn't find anything obviously wrong (however the previous owner did a real number on the wiring in my truck).

Feeling at a complete loss I decided what the hell, I'll just disconnect the battery cables and reconnect them. Well it did the trick and the truck started right up when I went to see if that had done anything.

I didn't notice if the cables were on the battery tight or not when I took em off but they definitely weren't corroded or anything.

[Farmstore34]

The small wire that runs from the positive battery terminal (along with the regular battery cable) had pulled loose from the black junction box on the inner fender. Somebody hadn't crimped the little ring terminal onto the wire very well and it finally pulled out. Of course, I didn't figure this out until I had R&Rd the starter to test it. Oh well, thats the fun of these old trucks! Thanks to all who responded!
Colby.
BTW I put pictures of the truck in the new photo album.

[cdowns]

thats why i hate crimp connectors other than for a temp fix ,theres nothing like a soldered joint for a permanent repair