81 K10 fuse panel layout

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RiverRat4

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Hey all.. I’ve read lots of posts and realize I need the fuse panel layout specific to my 81 K10. I’ve used similar layouts from close years but it seems there’s something unique about the 81’s. Does anyone have a fuse panel layout for an 81 k10 manual trans?

My symptoms are intermittent crank no start then poof! She starts like she was ready all along. The other issue is a continuous battery drain in the off position. I have to keep a battery charger on her if she sits idle for more than 36 hours.

Thanks for any help offered!
 

Strick

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I would look somewhere besides the fuse gang for your issue. If you have intermittent starting issues I'd address the ignition starter switch (column mounted) first. This may alleviate your starting & parasitic draw issues in one repair.
There are a few methods to check for the parasitic draw & someone besides me will post 32 pages of procedure for you to follow.
You can "easily" unbolt the ignition starter switch & use a small screwdriver to actuator the starter where the actuator rod attaches. Try this first & see if you have any hesitation our paused starts.
 

Strick

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Next you could look for neutral safety switch issues...
 

Ricko1966

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Crank no starts aren't caused by fuse box,neutral safety switch,and very very rarely by ignition switch. When you say crank no start, you do mean the starter motor cranks the engine over ,whir,whir,whir,whir but the engine doesn't start correct.
 

RiverRat4

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Thanks everyone for the replies. Let me describe better what goes on. First of all I have officially named her "Miss Priss" cuz she just starts whenever she wants to. Being she is manual Transmission, If I was to stall her out then try to start her back up, I may have to wait a bit for her to decide when she is gonna start. I will say that I've stuck my foot up under the dash and wiggled on the wires and sometimes that is enough to get her to start but not always. Sometimes the first start of the day makes me wait and "wiggle", sometimes if I go into a store, I always hold my breath when starting to see if she wants to go or not. I do like the direction of the neutral safety switch but I was under the impression that wont even allow the engine to crank at all? She will always crank, sometimes give a couple backfire pops but then its just a dry crank. I wait.. wiggle the wires some, then all of sudden, she comes to life and decides she will allow me to get where I'm going.

issue 2: I have a parasitic draw ( I like that description), I have been leaving a smart charger on her whenever I put her in the garage otherwise in 2 days, that battery is deader than a door nail. (where did that ever come from anyway?) So I keep her on a trickle charge, If I park her out somewhere where she will be sittin for a day or two, I have this solar charger thing that I plug into the cigarette lighter and that seems to always allow her to crank. Wether she starts or not is up to her.

So, correlation between the two? I can't help but think so. Here is another clue maybe? I began pulling fuses with an ohm meter connected to the Red Hot that shows it responds to changes in resistance when the door is opened and the courtesy lights are supposed to come on. (yes, battery disconnected). I started pulling fuses and one fuse removed a measurable resistance completely from the circuit. I have no idea what that fuse goes to because the panel isn't marked. So... that was why I was asking for a panel layout.

The no crank no start is probably something else? But... if that is an ignition fuse? maybe ......?
 

Ricko1966

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Parasitic draw take off the negative battery cable,put a test light in between the battery and tge negative cable. Does the test light light? If so unplug the 2 prong connector from the alternator. Is the light still on? Start pulling interior fuses one at a time until the light goes out. Post back.As for your crank no start it's still not a fuse,and it's not a neutral safety switch it is very possibly the electrical part of the ignition switch on its way out,or a wire broken in it's jacket. I'll try to find you the color for the coil primary wire at the switch later. That is the wire it would be with a crank no start.
 

RiverRat4

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Ricko, I will do exactly as you described and report back. Look forward to any color coding you might be able to provide.
 

Ricko1966

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Ricko, I will do exactly as you described and report back. Look forward to any color coding you might be able to provide.
Sorry,forgot to look. Not home right now. Sorry
 

RiverRat4

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No worries, I did pull fuses and did get a resistance that went to zero on one fuse in the upper left half of the fuse panel but I have no idea what it does cuz the panel isn’t marked anymore. Not dash lights, not radio, not headlights or wipers, not cab lights. Must be something going out under the hood?

Ok I failed to mention there was an LS swap done and there is a new relay set up separate from the new wiring harness under the hood to the ECU. The little fuse block that came with the new harness has 4 fuses in it and two relays. One of the relays isn’t being used because a guy put in another one wired to the pink wire and the hot to the ECU so whenever the key turns on the pump starts pumping which always does even when she won’t start. I can’t help but think that pink wire is good and consistent with the ignition switch to fire up the fuel pump and ECU. Am I thinking right?
 

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one fuse in the upper left half of the fuse panel but I have no idea what it does cuz the panel isn’t marked anymore.
Post a pic and we can probably tell you. Choke maybe??
 

RiverRat4

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Ok here’s the fuse panel. What do these 4 fuses up here do? Im pulling each and seeing what shakes out. So far one out and nothing changes to interior
 

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Jgonick

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I think I labeled yours correctly- double check with attached fuse block diagrams
--
only 81 diagram I could find was a little fuzzy-sorry- looks the same as the cleaner 84 though
 

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Last edited:

RiverRat4

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Absolutely amazing! Thank you so much!! Now I can begin!!

Oh…. Do you happen to have a diagram schematic placement of the neutral safety switch?

Took miss priss out today put about 100 miles on here running into town and back. Anytime I stopped it was a gamble if she would start or if I had to wait till she decided to. More times I waited than not.

Finally got home and backed hee in the garage all fine and dandy.. went to start her to move her out of the garage and nothing! It’s as if the neutral safety switch failed. Seat belt light comes on, things power up, fuel pump pumping.. no crank at all now.

Did whatever was going finally go? So now I need to figure out how the neutral safety switch is wired and if it’s doing Whats it’s supposed to do.

Love it!!!
 

AuroraGirl

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Absolutely amazing! Thank you so much!! Now I can begin!!

Oh…. Do you happen to have a diagram schematic placement of the neutral safety switch?

Took miss priss out today put about 100 miles on here running into town and back. Anytime I stopped it was a gamble if she would start or if I had to wait till she decided to. More times I waited than not.

Finally got home and backed hee in the garage all fine and dandy.. went to start her to move her out of the garage and nothing! It’s as if the neutral safety switch failed. Seat belt light comes on, things power up, fuel pump pumping.. no crank at all now.

Did whatever was going finally go? So now I need to figure out how the neutral safety switch is wired and if it’s doing Whats it’s supposed to do.

Love it!!!
you had to wait ? Thats not a neutral safety switch
Thats likely something else
Playing with the shifter or putting it in neutral, is the neutral start switch

You should explain what happens when you try to start it, and what is different about when it works

Is it crank, no start
No crank, sputters, etc
 

RiverRat4

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Ok sorry to auto dump all my woes here without doing my homework first. I guess it gets to be a habit to hit the easy button and wait for fixes to magically appear at ya’ll expense.

So… figured out the no crank situation. Seems the little plastic hook that goes in the clutch pedal broke off and depressing the clutch no longer allowed crank. I pulled it out as far as it will go and left it there so no more annoying neutral safety switch until I get around to replacing it.

However, after viewing the fuses from the diagrams sent by JGonick (THANK YOU!!!) I doubt anything in the fuse box is causing my intermittent “crank no start till she wants to start” situation. I will however continue to search fuses allowing parasitic draw on the battery when she is off and tucked in at night.

Now im kinda thinking I should identify wires in the column that could cause a crank no start situation, but I can’t help but think if it cranks, it has power.. Argggh..

So when she cranks with no start, she will typically backfire due to residual fuel in the cylinder with no spark? Once that burns out she just dry cranks. All the while, the fuel pump is pumping. I’ve not had the ability to test for fuel pressure at the fuel rail during the no start situations. I need a second person for that. One to crank, one to depress the little pressure relief valve on the rail. If this is all intermittent fuel supply, I will be embarrassed.
 

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