No start, no lights…

[Cu1n81]

Hey everyone,
I have a 79 c10, SBC 350. Been noticing a slow sluggish start when hot. Yesterday the truck wouldn’t do anything. Turned the key and nothing. The cab light starts off really dim when I get in the truck and gets brighter the longer I leave the door open. If I hit the key to crank it the light goes off. If I turn on my head lights the cab light goes off. No dash lights or radio.

Battery has 12.5 volts. The main driver side fuseable link is showing 5-6 volts. I have checked the battery grounds. Looks good. Starter ground is good. Wiring to starter looks solid. It’s a fairly new starter.

Where do I start? Thanks!

 

[Randy and Easton]

Have you checked all your grounds? Here is a list of the ones you need.

More critical than you might think… don’t ask us how we know…

Randy and Easton

 

[RustyPile]

Remove and clean both battery cable terminals and battery posts,, Sounds like you might have some corrosion going on. If this doesn't fix things, then load test the battery. If you don't know how or don't have the equipment to do this, places that sell automotive batteries can do it for you. Many bad batteries will show 12.*** volts under a no load condition, then fall flat on their face when a load comes into play. Simply put -- having volts is one thing, amps and the ability to delivery them is another....

 

[Ricko1966]

First thing I'd do is clean the battery terminals that will probably fix it. That's where I'd start.

 

[midwest]

I took my last battery to one shop and they stuck it on a tester and said it was good 20 seconds later. I then took it to my local Carquest and they have a load tester, that took like 45 minutes. The print out showed it was bad. Some kid with a voltmeter at Autozone saying it has 12 volts its not a reliable test...

 

[F-64]

Fusible link is not good.

You should have maybe 0.2v drop on the other side of the fusible link.(battery 12.6v fusible link 12.4v)
You have a voltage drop over 7 volts.

Most likely the fusible link is holding on by a couple of strands of wire.

Put your meter on DC V.
Key on
Engine not running.

red meter probe on positive battery post(post is the metal part of the battery)
black probe on both sides of fusible link(close to battery---far from battery)

The side closest to the battery should measure very close to 0.0V.
Any higher than 0.5V then you have too much resistance on that section of wire to the battery.
When you move the probe to the other side of the fusible link the reading should be the same as the first. As close to 0.0v as possible.
If the first reading (fusible link-side close to battery) is very different from the second(fusible link--side far from battery)....Then your fusible link is bad.