I broke my new truck

[Juan Cano]

Long story it all started with trying to fix the dome light which led to a new headlights switch (didn't fix anything) which led to removing the dash because it didn't fit well (had to get more clips). Now I am putting it back together, put the dash in, trying to wrangle the freakin gauge bezel in, and suddenly, truck is dead.

Dead.

Lights turn on and battery is ok, but truck just clicks, no lights on dash. Someone suggested checking the Neutral Safety Switch cable coming loose but it's not loose, it's on firmly. Seems like a Neutral Switch issue but the switch seems fine plus it's so far back there's no way I could've hit it. Wife drove the truck yesterday and no issues. Then I worked on putting the dash/gauges back in. So something happened there.

What else besides the Neutral Switch could cause this?

I looked under the dash behind the column and all I found was this plug that is not hooked to anything. But it doesn't mean it was hooked to anything to start with right? These old trucks. I couldn't find where it goes.

1986 c10 Silverado, in C+ shape.

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[Rusty Nail]

Did you check the dome light?

 

[75Monza]

Curious, when you removed/installed cluster was the battery unhooked? Possible you popped a fuseable link out to the starter. Another thing I would check is plugs on back of cluster, if not seated right might have a missing connection through? Also, check the harness plugs on the column for the key switch, I've bumped that loose before trying to wedge arm up through to get to the speedo cable.

 

[75Monza]

Something I found that is related to dash lights...

Switch the running lights ON with the dash lamp dimmer rotated all the way counterclockwise. Use a test light clipped to a verified good ground to probe both sides of the Instrument Lamps (INSTR LPS) fuse.

• If both sides of the INSTR LPS fuse are 'hot,' probe the gray wire at the instrument cluster harness connector with the test light:
  
  • If the gray wire is 'dead' - verify that the INSTR LPS fuse is making good electrical connection to both of its terminals in the fuse block, then locate and repair the open in the gray wire between the INSTR LPS fuse and the instrument cluster harness connector.
    
  • If the gray wire is 'hot' - verify all of the dash bulbs are good, check the electrical connection between the harness connector and the instrument cluster circuit board (PCB), and check the instrument cluster ground connection to the cab sheetmetal. Using a pencil eraser, gently burnish the bulb socket connections to the PCB being careful to avoid peeling the copper foil loose from the PCB.
  
  
• If only one side of the INSTR LPS fuse is hot, replace the INSTR LPS fuse and locate the short-to-ground in the wiring between the fuse block and the PCB. Make sure the PCB isn't grounding to bare metal.
  
  
• If both sides of the INSTR LPS fuse are dead, probe the dark green wire at the headlamp switch with a test light:
  
  
  • If the dark green wire at the switch is hot - verify that the INSTR LPS fuse is making good electrical connection to both of its terminals in the fuse block, then locate and repair the open in the dark green wire between the headlamp switch and the INSTR LPS fuse.
    
  • If the dark green wire at the switch is dead - probe the orange wire pair at the headlamp switch:
    
    
    • If the orange wire pair is hot - check all wire connections to the headlamp switch and/or replace the headlamp switch, as necessary.
    • If the orange wire pair is dead - probe both sides of the Tail/Courtesy Lamp (T/L CTSY) fuse in the fuse block:
      
      
      • If both sides of the T/L CTSY fuse are hot - verify that the T/L CTSY fuse is making good electrical connection in the fuse block, then locate and repair the open in the orange wire between the T/L CTSY fuse and the headlamp switch connector.
        
      • If only one side of the T/L CTSY fuse is hot - replace the T/L CTSY fuse and check for shorts-to-ground in the wiring between the T/L CTSY fuse and the PCB. The 'short' could exist anywhere between the fuse block, the headlamp switch, and the cluster PCB.
        
      • If both sides of the T/L CTSY fuse are dead - check electrical connections through the firewall bulkhead connector, as well as the fusible links connecting the 12-gauge red wires to the firewall junction block in the engine compartment and the 3/8" battery cable stud on the starter solenoid - repair as needed.

 

[Rusty Nail]

@75Monza

You might have missed the rest of the story...like Paul Harvey and ****.

https://www.gmsquarebody.com/thread...rt-circuit-questions.30571/page-2#post-684156

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Who?

Lookout dude has been hacking that thing up with led lights - NOW he's chasing electrical gremlins.

 

[75Monza]

Yep, never seen anything about LED's. Hackers are their own worst enemies, lol.

 

[Juan Cano]

Thanks for the ideas; I think this truck does not have a Neutral Safety switch at the bottom of the column but instead what they call a Mechanical Safety switch built into the column and it somehow engages with the key cylinder to make it start on P and N. Seems some magical wiggling is needed.

To be clear, truck was running an hour before. This all happened while installing dash and the gauge bezel only, no electrical connections or wires were involved in this process.

May be caused by moving the steering column up & down to allow for clearance and also shifting down to 1.

 

[75Monza]

Time to grab a good meter and start testing points off the wiring schematic. If you don't know how to test electrical wiring, better off having someone that knows what they are doing or you make a bigger mess.

 

[Juan Cano]

Thanks 75Monza. Like your Bob Ross avatar.

 

[Scott91370]

Correct about not having a neutral safety switch. It is built in to the key mechanism on 85+ which keeps the key from turning forward unless the trans is in P or N.

 

[Juan Cano]

Yes; now I have to figure out why the heck it decided to stop working. I'll try more key wiggling and shifter waggles later today, and check for loose connections. Any other tips?

 

[Scott91370]

I wish I could help. I came out one day, turned the key to start and I get one click and that's it. Been about 2 months and still haven't figured it out.

 

[Juan Cano]

Think it's time to bring an actual mechanic. I checked the ignition switch to see if the lever from when you turn the ignition key that moves the ignition switch was out of whack (btw, what a PITA to get to it and remove and put back together!) and nothing. Just 1.5 hrs of wasted time and a neck ache.

I failed to mention that when the truck decided to not do anything anymore, the power locks also stopped working. This makes me think this has nothing to do with ignition. What wire could be disconnected to cause this but still have working lights?

I did try testing wires but I just suck at it. I don't even know where to start; how do I get to a wire to test it? Pull it out of wherever is at?

 

[75Monza]

Use a test probe...honestly, get a mechanic. Will be worth the money in your case.

 

[crpntr78]

Also, there is a fusible link around the steering column on the engine side of the firewall. Check that as well. Had one blow there when I hooked the battery up backwards. Same symptoms as you describe.