Electrical help. No power when key is turned.

[Dodonne2]

Still no power to cab at all. Here is where I am currently tracking. I have all wires off starter solenoid except large red battery cable coming from batt. I will start attaching the 4-5 other wires that go on the hot side of the starter solenoid and as I attach each wire I am checking for a voltage drop at the solenoid. The voltage drops to 10v when I attach the black/orange wire which runs into fuse panel. Then I attach another of the yellow wires which I believe runs to passenger side door panel and voltage drops to 1. These two wires also carry around 1 volt unattached to the solenoid.

Why would they hold voltage unattached to soleniod? Because there is a bad ground somewhere back feeding the circuit?

Why do these two wires cause voltage to drop at the soleniod? A bad ground somewhere? Could a bad connection for power doors or cruise control cause this bad of electrical loss?

 

[Dodonne2]

I have no 12v to fuse panel now. Used to have 12.5v to fuse #1 the stop hazard wire, but now don't have that 12.5 anymore after taking batteries in and out of truck. Bad battery cable? They have no corrosion and look newer. Truck has over 400k

 

[franklin2]

Hook that wire up that makes the voltage drop to 10v. Leave it hooked up. Then take your meter and start testing backwards to the batteries. See where the voltage goes from 10v to 12v. If it never does and you have 10v on the batteries, your batteries are dead. You cannot test the battery voltage with them just sitting there, you have to put a load on them. That is why they have those large chrome battery testers with the load resistors in them.

But this load that makes the voltage drop will work also. If you find the batteries have 10v, and you get them charged back up, then you can figure out where that drain is coming from. Could be a bad alternator diode.

 

[Rdnck84_03]

I don't remember what year you said your truck was, but the obs trucks with power door locks have a circuit breaker in the fuse box. I have had 2 different trucks neither were idi but a 94 gasser and a 97 powerstroke that would drain the battery until I pulled that breaker out.

I never tried to diagnose what was shorted out because I never locked either of them. But on both of mine the breaker was hot enough to burn your hand, that's how I accidentally found the battery drain on the first one.

James

 

[Dodonne2]

So after racking my brain and much help from this forum, thank you, I figured out the problem. The large 6 gauge wire coming off the battery terminal that connects to the starter solenoid had no continuity. I have no idea how or why because it's the best looking battery cables I've seen on an older truck, they look new. Lesson is test your continuity!