Truck just died and no electrical power??

[LT102]

Truck is idling as it should while making some carb adjustments when it just shuts off. Turn ignition key, nothing. Checked for headlights, nothing. No electrical power at all. Check wires on ignition switch all look ok, fuses look ok, battery connection good and no loose wires (that I can find). About 15 minutes later I try ignition and it starts right up and electrical power seems correct. Afraid to take it down the road as it may die again. Any ideas?

[magwakeenercew2jh]

Originally Posted by LT102

Truck is idling as it should while making some carb adjustments when it just shuts off. Turn ignition key, nothing. Checked for headlights, nothing. No electrical power at all. Check wires on ignition switch all look ok, fuses look ok, battery connection good and no loose wires (that I can find). About 15 minutes later I try ignition and it starts right up and electrical power seems correct. Afraid to take it down the road as it may die again. Any ideas?

What are you running?

When you say, "Turn the ignition key, nothing", does that mean ABSOLUTELY nothing?

No lights, gauges, turn signals, radio, TV, refrig, etc.?
How much charge at the battery?

If there's a full charge there, where DO you have juice?

Although experienced, I'm no electrical prize like some of these more wise guys....
But a little more info would be good.

Even if you have to "remember" what was cooking when it happened.
Tough to figure out when everything is working *perfectly*.

I share your pain...Just not right now.

[LT102]

71' C20 with rebuilt 350. Nothing changed on the electrical on the restoration.

[LT102]

Nothing was on other than the engine. No headlights, radio or dome lights. When it died it absolutely died, dead. No power anywhere. After about 15 minutes of searching for the problem I tried to restart and it fired up fine and headlights where nice and bright and things seem fine. But I don't want this mystery to come back driving down the road.

[Davidf]

My first point of investigation would be the ignition switch. Could be a temperature related fault. Don't forget new means nothing, it could be a BOOB (bad out of box) part.

[LT102]

I agree to check the ignition switch, but there was a total loss of power that is not controlled by the ignition switch, ie the headlights. I have in the past experienced the BOOB.

[68350]

Is the wire from your battery to the junction box on the passenger fender in good condition? That wire provides power to the entire truck

[Jonlopes]

I was thinking of a bad battery cable or at least a dirty connection. easy to check and free to fix if it is crudded up at the battery post.

[Secret Squirrel]

I tried to jump my motorcycle with my truck once. As soon as I hit the start button it completely shut down the truck. That is the only time I had ever seen a truck completely loose all power. Only thing I could figure is to check the power going into the fuse box, it's the only place where all electrical is connected right. Totally just guessing but if nothing else it's a free bump

[LT102]

Excellent suggestions. I will check them and report back. Thanks!

[7tee]

After a complete tune I was driving down the road and all of a sudden it just shut of, pulled to the side of the road and it started. Next day same thing, turned to be a bad brand new module. Changed it and good to go...

[mikeshome]

I would check the conections going to the fusible link just off the battery,Maybe the ground cabbles to engine.Check tight at battery first.

[VetteVet]

If you have a stock factory wiring system there's only one place that will kill all the power to the truck including the key off power.It isn't the battery or the fusible link because once the truck is running it gets it's power from 2 sources. The battery and the alternator. remember the alternator is self sustaining once the engine is running and it's charging. You can lose power from the battery and the alternator will supply current to the system although it may default to full output voltage.

The alternator and the battery both supply power to the cab feed wire which goes into the firewall block by the master cylinder. It's the 12 gauge red one, This is the only place where all voltage to the truck is concentrated. You need to pull the firewall block apart and check the connections on the red wire and the other wires as well.

Once the red wire passes through the block it feeds the ignition switch, the headlight switch, the fuse panel, and the horn relay, so if all those are dead then the problem has to be in the firewall block connection otherwise one or the other would still have power.

Here are the diagrams of the power circuits in the truck.

This is the engine side showing the battery and alternator feedwires to the four way junction and the one red wire going off into the cab.



This is the red wire after it comes through the firewall block and splits going to the items I mentioned



this is the continuation of the red wires that feed the headlight switch and the ignition switch.

[GASoline71]

Originally Posted by 68350

Is the wire from your battery to the junction box on the passenger fender in good condition? That wire provides power to the entire truck

This. ^^^ Mine has a fuseable link in the wire. Yours might too. Check the fuse or the connection at the passenger fender for corrosion.

Gary