Whoops, trouble shooting a gauge cluster/electrical issue (1 Viewer)

Joined
Sep 8, 2003
Messages
5,269
Location
Bozeman, MT
Back story, I was having intermittent electrical issues on my 76 FJ40 (11/75 manufacture) last year. Found this issue was my amp meter had a loose bolt on the post. When I discovered this was the issue I was elated, cried a few happy tears and did a little dance...

In my celebration I forgot to disconnect the battery for the reinstallation so when I went to reinstall the cluster I managed to ground the whole thing. Sparks flew, smoke rose, pee’d a little and tears were shed again.

So I pulled the whole cluster today (disconnected the battery) and need to figure out what’s up.

What’s working...
  • Headlights
  • Ignition
  • Amp meter
  • Turn signals
  • Anything required to run the motor
What’s not working:
  • Seems like everything else...
  • No dash lights
  • No fuel gauge
  • No oil pressure
  • No voltmeter
  • No brake lights
  • No gauge lights
  • No fan
I know enough to know my white/blue stripe is from my alternator, my solid white feeds the fuse block.

Not sure how to trace the circuit on the back of the gauge cluster through each gauge. I’m assuming I’m trying to find a short at this point. Not too sure what’s connected to what and where to start.

Fuses are good.

Fusible link is good (bypassed at the moment)

Any advice moving forward would be helpful. I’m in the deep end of the pool and can barely doggie paddle.

Thanks in advance

here’s what I got...
57B74F80-18F7-4BAD-BC80-A87D8370CBF0.jpeg
 

thebigredrocker

SILVER Star
Joined
Nov 6, 2013
Messages
3,447
Not sure if there's any info pertaining to your situation here:

also a good thread:
 
Joined
Jul 11, 2015
Messages
415
Location
Las Vegas
First off you need to repair the circuit board that got fried. Either solder together or bridge the gap with a little piece of wire. Solder wire in if the gap cannot be bridged with solder.

6A11B114-5D42-4790-9E58-30CC517F93A5.jpeg
 
Joined
Sep 8, 2003
Messages
5,269
Location
Bozeman, MT
Sweet, I went ahead and bridged the gap with solder, I have confirmed continuity, plugged it all in and blew the rear brake light fuse, nothing different from before.

I did confirm I have power to the fuse block, the blue/white stripe wire splits and I’ve got power to both ends
 
Joined
Sep 8, 2003
Messages
5,269
Location
Bozeman, MT
I thought I would bring this one back up.

I pulled the old gauge cluster and popped in a working unit from a 78 today and nothing changed.

What’s working...
  • Headlights
  • Ignition
  • Amp meter
  • Turn signals
  • Anything required to run the motor
What’s not working:
  • Seems like everything else...
  • No dash lights
  • No fuel gauge
  • No oil pressure
  • No voltmeter
  • No brake lights
  • No gauge lights
  • No fan
I am assuming I welded some wires in the harness at this point. Short of replacing the wiring harness, any ideas of what to pursue next?
 

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