dash lights wont work

[Duck95]

I replaced two light switches, one was faulty so I got a replacement and all my dash lights quit 2 weeks later, i had the dash out checking wires and checked all the fuses. Could it be the printed circut behind the dash? its aggravating as all heck!!!

[pholliday1]

There's actually a few posts on this and usually a few different culprits. But Find the schematic for your truck and start checking voltage from there are your tail lights blown also? 

[Duck95]

No at first all my lights quit so i replaced the switch an everything worked then it done it again, new switch an it was all good then the dash lights went out one night but everything else still works.

[bd]

Refer to the appropriate year wiring manual in the Tech Section of the Forum, about half-way down the page.


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.
  

Edit: procedure refinement

[hondarider188]

I have the exact same problem with my truck and i havnt been able to find it. And what bd says is great info ill have to try also. so if you find the source be sure to post back and let us know what it was.

[Duck95]

Havent had time to check it out much been in the hay all week, but i got to thinkin i want to restore/redo the truck in a year or two an I have a buddy that pulls an had a custom diamond plate dash panel made. The original temp, oil press gauges dont work and i have manuals which i prefer so i thought about getting a wiring harness an just wiring up what a need and having a custom dash made, would this be possible, has anybody ever done this?

[Irish_Alley]

possible yes but if you mount the gauges flush they will be pointed down to your crouch have to angle them up one way or another
http://forum.73-87chevytrucks.com/smforum/index.php/topic,9759.msg66671.html#msg66671

[blazing816]

That is what I did for my gauges because only the fuel gauge worked when I got it (so I kept that and the speedo after replacing the speedo cable, just put white stickers on those).

http://forum.73-87chevytrucks.com/smforum/index.php/topic,24709.0.html