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PLEASE HELP! '76 K10 won't even turn over!

handloader90

handloader90

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Good Evening,

Here's the story. I've got a '76 K10, never really had any electrical issues... small bugs that were easy fixes, but nothing like this.

About a week ago it had a hard time turning over, but it turned over. Thought it was the battery so I let it idle for a good 45 mins. in the driveway. Turned it off, fired up with no hesitation. Went out the next morning for work and all I hear is click, click, click, click, click. Ok, I know this sound... not enough juice in the battery. Put the battery on the battery charger, battery is now fully charged and i throw it in and click, click, click, click, click. So I'm like what the hell?! Took the fresh battery out of my Jeep and hooked it up in the K10. Nothing (Not even clicking, just a dead truck)! I pulled the Accesory/ Headlight knob, got lights for a little while, pushed the knob back in, pulled it back to on and nothing... no lights whatsoever. My gauges are working, at least the batttery gauge, it's reading between 12V-15V.

Battery terminals are clean, battery wires/ battery wire connections are clean.

Also, I was using my K10 to try and jump a dead ass '86 Jimmy, I even went so far as to take the battery out of my K10 and put it in the K5 (But I've ruled out a bad battery) Could I have burned something up while I was trying to jump the Jimmy?

I REALLY NEED MY TRUCK RUNNING!

Any and all suggestions please! I don't have means to test wires as of now, will be picking up a tester tomorrow.
 
If the battery cables are good,not all corroded at the battery terminals, I'd suspect a burnt fusible link --there are two on the red wires that go on the starter solenoid stud,behind the positive battery cable...most GM trucks have another one near the power brake booster too,that protects the cab part of the wiring harness..the two near the starter might be in a metal pipe near the bellhousing...those supply power to the whole truck--so if your headlamps wont work,I would suspect those..

If you can get at the solenoid (its buried under the exhaust manifold and hard to reach or see),you might be able to use a screwdriver to jump the battery cable to the "S" terminal on the solenoid,it will have a purple wire on it--if it cranks then (make sure its in park or neutral if its a manual first!),then it is likely the fusible link(s) failed..it will probably just crank if you jump the solenoid,since the coil isn't getting power most likely,it wont fire up --but be ready in case it does..
 
Thank you for that info! The truck is automatic.

I have fusible links (I believe two of them) mounted on the firewall close to the middle but more towards the drivers side, the one on the left has holes in the housing, exposing the actual wiring, The wire that I can see through the holes looks kind of black and the wire as a whole feels kind of mushy. Could this fusible link be the culprit? If so, what could have cause this? As mentioned before this kind of just suddenly happened and then it just got worse and worse to the point where the engine won't even turn over.

Ok, so the let me ask you this. If I wanted to go ahead and replace all wiring going to the starter... how would I go about doing this? Don't some of the wires hook up to the alternator (maybe I was seeing things when I swapped in a new starter back in Jan.) Is there a harness or would I have to piece the wiring together, what gauges if this is the case. I want to eliminate any of these possible issues by just replacing possibly bad wiring. I will test the starter first thing in the morning (I know how to test the starter with jumper cables and a screw driver) I was going to pull the starter and test it this way in the morning unless this method is not recommended.
 
Go to the post here labeled "This kind of crap gets people hurt" and read it,I just posted there about how I "improve" the fusible link wiring at the starter..

Its very possible your fusible link failed,and it could be due to a number of things--old age and corrosion,too many amps drawn thru it from added lights or other electrical loads,or a short in the wiring somewhere--it was designed to "save" the whole harness from frying by being sacrificed...

Those 2 wires at the starter usually go into the main engine harness behind the engine...you'll probably have to take off the metal pipe they run thru next to the dipstick tube for the tranny and pull them out,and unwind some of the tape wrap on the harness to replace the wires..It's easier to just follow them by the color code to the other side where they go into the firewall or fuse box and cut and splice them in there instead of dealing with all that--and then your sure they are "good" all the way to the battery...
 
Ok. Gonna check that thread out as soon as I'm done writing this.

What gauge of wire would I use for all of this. Also, as mentioned before one of the fusible links on the firewall is burnt up... where does this lead to?

I want to replace ALL fusible links and any possible culprits, hopefully that's the fix and if not it will at least let me mark those off the list as possibly problems.
 
I use 8 or 10 gauge wire,and not "house" type stranded wire,there is a difference in the number of strands and the insulation--either "will" work,but the automotive wire holds up better to the high heat and amp draw..

The fusible links near the brake booster I am pretty sure protects the cab's wiring,so if they fail,nothing in the cab will work--no headlamps,ignition,etc...but if the two at the starter fail,no power gets delivered to those other 2 links,so the same results..
 
Ok, looked that thread over.

I read the fusible link mod post and copied and pasted it into word. I would like to do this mod if you can explain to me in detail how to go about it and what gauges of wire to use and any other little doodads to throw in while I'm at it. My weekend is dedicated to fixing this problem and taking my time with preventative fixes that will prevent this from happening in the future.

Also, please forgive me for asking all of these questions, some may seem redundant, but I generally only learn by visual means or having something explained in to depth so much that a child would understand.
 
Which gauge is the more preferred... 8 or 10? I only use auto wire for automotive uses, don't want a failure because I Was too lazy or cheap to use the right thing.
 
I'm going to install new battery cables tomorrow, new grounds (all of them), I want to do the fusible link/ starter purple wire mod, replace all fusible links, test starter (if it's dead I have a lifetime warranty).

Any other recommendations for anything else that can be checked out, replaced or modded please let me know.

Also, I'm not running any additional accessories besides my tach which is fairly small.
 
To me it sounds like a connection issue.

And go with the biggest wire you can within reason. Heat creates more resistance, which creates more heat, which creates more resistance, and so on until something fails. Bigger wire helps with these issues. I forget the scientific terms. I've been drinking a while tonite.
 
When you say "Connection Issue" what are you speaking of specifically?

What is the thickest gauge wire that one can safely use for this application(s).
 
The only downside to using 8 gauge is its harder to get the right connectors and crimp them on well enough,10 gauge is sufficient ,and what GM used originally I think,but overkill is not a bad thing when it comes to wiring--especially those wires that bear the brunt of the entire electrical system..

You may want to try google and see if you can find a wiring diagram for your year truck ,I have a crappy Haynes manual and you need a magnifying glass and 20/20 vision to "read" the color codes and trace the wires,the pictures are dinky and suck!..having a good wiring diagram makes it much easier,if you can read a road map,you can trace which wire goes where and it wont be so confusing and intimidating..I'll be glad to help if I can...I know without pictures wiring is tough to understand..
 
Ok. I'm just trying to wrap my head around the fusible link thing... Is it basically a piece ove wire spliced in, how long should a fusible link be? I guess I just on need the down and dirty on fusible links period.

diesel4me - Can you explain in detail how to do the starter wiring mod? What lengths of wire am I looking at?
 
Here is a wiring diagram of the underhood wires,hope its readable..you'll see the two fusible links noted at the starter solenoid and the ones you mentioned at the firewall near the brake booster...they omitted the battery in the diagram,how nice of them,that doesn't make it any easier to figure it out really..

I found that diagram on google ,but it was much easier to read than it copied here...

The length of the wires you'll need depends on your particular truck,where you cut and splice them,etc...I'd get a spool of 10 feet at the least,15 feet would be better as 10 might be not quite enough...

Before you go too far,make sure the battery terminals and the cables where they connect are clean and scraped down to bare metal,and if there is any smaller wires coming off the main battery cables ,make sure those are still connected to ground or power and not fried looking or broken too,those can kill the power too...

I'll have to turn in soon,but will be able to guide you thru this more tomorrow..

81-87_V8_engine.jpg
 
OK, here is something you need to know. A fusible link is just that, a FUSE. Up until a few years ago, no one really made actual fuses in the current levels that were needed for those circuits.
At least not cheap or small enough for automotive.

So, what the car companies did, was splice in a section of wire that was smaller than the supply wire it was protecting.
They put in a safe place, and usually used a special insulation that was flameproof.
Its supposed to melt before damage occurs.

Never replace it with larger wire.
Here is a link to a quick explanation. http://www.madelectrical.com/catalog/fusible-link.shtml

Often the fuse is color coded.

Nowadays, you can buy actual plug in fuses in whatever amperage you want. Lots of folks have upgraded their systems by adding a high current fuse panel in place of the links.
But, to be honest, there is not a lot of advantage to doing it. Fuses will respond faster than links, which might help save some electronics.
And they are easier to see when blown.
But links work.

There is nothing wrong with upgrading the rest of the wire to larger size. Just don't increase the size of the link.
Most auto supply houses sell the link material.
 
Awesome info that cleared some of my questions up, thank you! How many gages smaller than the supply line should the fusible link be?
 
If I remember correctly the fusable link is a either 12 or 14 but dont quote me on that. Your neutral safety wire is the purple one, that actually doesnt draw that many amps so if youre replacing it you can go with the same size wire. Its really just the trigger wire to tell the starter to do its job.
 
The rule of thumb, is four number sizes smaller than the feed.
Remembering of course that sizes go down as the number goes up.

So, to protect 10 gauge wire, you would use a short piece of 16 gauge.
The length is important, but not super critical. Around 6 inches is standard I believe.

The original factory sizes are listed in lots of places, but I don't know a link right offhand.
Some parts houses might have them.
 
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