No power when key turned on

[PugDad]

ok, weirdest thing. Rig is 1977, w/ 350. Basic rig, no mods.

I went out to start the truck. No power.

Typically when I turn the key on, the voltmeter kicks up, and the radio turns on. This time, nothing. Nada. Dead.

We had a really cold snap, and I thought maybe the battery was dead.

Grabbed the multi-meter, it showed 12 + volts at battery. I switched to a test light. It lighted up at the battery, would not light up at the positive cable at the starter.

I decided to take off the battery terminals and clean them. When I put them back on, the truck fired right up.

The next morning, the truck fired right up. My wife decided to take it to the store. She called me from the store and said it wouldn't start.

I went down there to check it out, and same symptoms as before..deader than a door nail. I tried taking of the battery terminals and reinstalling again, but no luck.

I took the battery to the shop and had a load test done on it...tested ok, recovered well.

aarrggghhh

Thoughts? I'm wondering if the starter switch got a glitch in it..after all it is 33 years old...

[Nodak mack]

had the same problem on my 77 turned out to be the starter now i got a ignition problem that i cant hook the battery up without the truck trying to crank and start.

[PugDad]

Your problem sounds like the starting solenoid is stuck in the "on" position.

My problem is that I don't even get pre-cranking voltage, like accessory voltage.

[allengator]

[QUOTE=PugDad;4362355]
Grabbed the multi-meter, it showed 12 + volts at battery. I switched to a test light. It lighted up at the battery, would not light up at the positive cable at the starter.
QUOTE]


Double check this... if you are seeing voltage at the battery, but not at the end of the cable on the starter. Then you have bad cables.

If you were testing at the starter terminal with the negative clamp for the test light cliped to the frame or an engine component, you may have a bad connection on the negative battery cable where it connects to the frame (or engine... wherever yours terminates...)

[old Rusty C10]

clean all your connections on your battery grounds and the starter and see what happens

[willett]

i would do a voltage drop on your main line into your starter, as well as your main ground lead.

the cable may look fine on the outside, but inside could be a different story.

and nodak mack, it sounds like your contact plate on your solonoid has welded itself shut. buy a new solonoid for $20 and it should work like a beaut!

[PugDad]

Originally Posted by willett

i would do a voltage drop on your main line into your starter, as well as your main ground lead.

the cable may look fine on the outside, but inside could be a different story.

I found and corrected a really bad ground lead. Didn't solve issue, but at least that is one thing out of the way.

At the starter, two 12 ga wires take off and disappear into a wire loom.

I think one of them emerges at the firewall, as there is a insulated block there with a red 12 ga wire attached to it.

When I check from that point to the batt neg, I'm only getting 9v. I'm not sure that is the "root" problem. I would expect a low batt voltage like 9v to show up on my voltmeter in the dash, but nothing is registering there when I switch the key on.

I know I need to fix this voltage drop. I'm gonna get under the truck and take the wires off where they jump off at the starter and clean em all up really good, and start checking again.

A schematic would be handy...

[willett]

the haynes manual has a pretty decent schmetic, i think that its about $20 for one and it has saved my a$$ a couple of times.

see if anything happens if you short your starter with a screwdriver.

[billnorman]

Sounds like you found a ballast resistor or resistive wire. On some old trucks the starter provided a 12 volt input to the ignition system at start and then it dropped to 9 volts or so running to make life easier on the ignition primary system. Anyhow, sounds to me like you need to really clean your terminals and cables. Someimes the terminal gets a film that will breakdown and conduct at starter load but have enough of a film to prevent charging current. Check ON THE BATTERY at fast idle you must have 13.8 to 14.2 volts or thereabouts to charge. If you have a side mount terminal check at the bolts. If you have top post check on the posts. If you have this voltage present, and your battery doesn't charge, it's deflicted. If you don't have this voltage anywhere even at the alternator, it's toast.

[allengator]

Originally Posted by billnorman

Sounds like you found a ballast resistor or resistive wire. On some old trucks the starter provided a 12 volt input to the ignition system at start and then it dropped to 9 volts or so running to make life easier on the ignition primary system. Anyhow, sounds to me like you need to really clean your terminals and cables. Someimes the terminal gets a film that will breakdown and conduct at starter load but have enough of a film to prevent charging current. Check ON THE BATTERY at fast idle you must have 13.8 to 14.2 volts or thereabouts to charge. If you have a side mount terminal check at the bolts. If you have top post check on the posts. If you have this voltage present, and your battery doesn't charge, it's deflicted. If you don't have this voltage anywhere even at the alternator, it's toast.

+1 on the ballast.... this wire supplies the ignition and the voltage is about correct... if you convert to HEI, then you need to "fix" this drop... otherwise it is normal....

since you cleaned your grounds and battery cables, have you tried again with a FULLY charged battery??

[PugDad]

I disconnected the battery, and got under the truck to check all the connections at the starter.

I found the that the nut was loose enough that I could wiggle the connector. Not the 4 gauge main battery wire, but the 12 g wire that takes off there and goes up to the system.

Tightened it up, reconnected the battery, and re-checked the voltage at the terminal block on the firewall...before it was reading 9.xx volts, now it's reading the same as the battery, 12.xx.

Truck started up...happy day!