Factory Electrical/Wiring/Battery Cable Layout Pictures on 1983 350 V8

[mistaake]

So, tomorrow I'm going to spend all day working on my recently acquired ran-when-parked-many-years-ago 1983 C20 with the 350 V8 and Automatic transmission and try to get it going.

Last weeks two-minute attempt to connect a battery gave me nothing. No gauges, lights, power anywhere, starter, fuel pump whine, anything... So clearly something's not connected. Could anybody with a similar truck please take pictures of where the cables that are connected to your battery terminals go? Because I have three fat cables in that area so IDK which ones are actually supposed to go on the battery.

Thanks in advance,
Michael

 

[chengny]

Only two connections to the battery. Both cables are black and have clamps on the ends that go on the battery posts.

The positive cable goes down and heads back towards the firewall. It is connected to the starter solenoid.

The main grounding cable clamps to the negative post on the battery and heads straight over to the engine. The connection at the engine end is almost always done at the alternator bracket.

The diameters of the battery posts are different - the positive is larger than the negative - and the respective cable clamps are appropriately sized so that;

1. The negative clamp will not fit on the positive post (without intentionally spreading it way open)

2. The positive clamp will not fit snugly on the negative post - no matter how tight you make it.

As far as the third big - unconnected - cable; I'm guessing but, it is probably the forward lighting ground wire. This cable is normally spliced into the main ground wire at the battery end and is bolted to the radiator frame at the other.

 

[mistaake]

Well, making slow progress. I did convert to side post terminals because $5 in terminals is cheaper than $100+ for a battery (I didn't have any spare top post batteries, but I had the spare side post battery)

Haven't put spark plugs back in (took the old ones out to check condition and spary WD40 into cylinders, some of them broke so I bought 8 new ones) nor have I reconnected plug wires. Was going to bump the key to start to see if the engine would turn... But was unable to do so. Made a video, hopefully this is all really obvious to somebody.

Thanks!

https://www.youtube.com/watch?v=Zo9AnYQLrNU

 

[mistaake]

Okay... so was able to turn the engine using world's best tool, the mighty breaker bar

Sprayed more WD40 into the cylinders to lubricate them. No, spark plugs aren't in yet.

Starter still doesn't work though. Absolutely nothing happens when I turn key to start. No clicks, no crank, nothing at all.

Clearly the negative and positive terminals are connected because the radio, headlights, etc. work. But some things (starter, voltage gauge) don't work.

Any ideas? Thanks!

 

[firebane]

For the starter to engage you need to ensure the purple wire is connected to the terminal at the 3 position on the starter and that the wire is not broken anywhere. From there its a matter of fuses and or bad wiring.

Also make sure you have 12v at your junction block on the firewall and if you have the room and be VERY VERY careful with a well grounded screwdriver you can jump start the starter but will need a way to stop the engine.

 

[mistaake]

OK... So now everything is working except for starter. Methinks it's either not connected properly or it's bad. I didn't see the above response until now but here's where I'm at.
By the way I did put in new spark plugs and reconnected wires. It's ready to go... just gotta get it to start

When in P or N I am able to turn key to start. In this case, the brake light gets slightly dimmer (barely) but the starter does not click or turn.

I think I was able to trace the other end of the mystery cable to something dangling near the starter... but I'm not sure if that's even supposed to be connected... maybe somebody replaced the starter cable at some point and just left the old cable in?

 

[firebane]

Find out the color of the wires at the starter. You should have 1 purple wire at the 3 position on the starter (closest to the engine).

Then off the big lug that runs to the battery you should have 2 more wires of which one runs to the junction block and the other runs to the alternator.

The 2 extras that run from the battery lug should also have fusible links on them.

The wire that is dangling has a connection for the starter but you will need to know the color of the wire to further diagnose. Sorry but its time to crawl under there and find out whats going on.