Hey guys, I have a 92 civic dx hatchback. I am having an issue with the gauge cluster back lighting and tail lights flickering. Before i realized it was just the cluster back lighting and tail lights, I checked the battery which failed so I replaced it, checked output directly from the alternator and it was fluctuating between 13.1 volts and 14.2 volts pretty rapidly. So I then replaced the alternator. To no avail, its still doing the same thing. Thats when I realized no other lights are flickering, ie headlights, clock , radio etc. I then remembered the gauge cluster lights and tail lights are on the same circuit. I checked to see if maybe the fuse was corroded but the fuse was good and clean. Has anyone had this issue and fixed it or does anyone have any ideas or what to check next? Thanks in advanced.

 

is the alternator voltage stable now after the replacement? no more fluctuating voltage?
does the tail light also flicker?

maybe check the following? (quick checks)

• dimmer switch - if you happen to have a replacement, you can swap it real quick to test
• 10A dash/tail light fuse - you said it looked good but why not just try to swap with another 10A to make sure

if nothing else solves the issue…

• seems like gauge lights 12V is fed off of 10A fuse and ground is provided by the dimmer switch (red) so you can check the voltage in between that.
  • if the voltage fluctuates here, check the voltage drop between both power and ground to isolate which one is bad
    • if the 12V/power is bad, fused circuit wiring is probably not good.
    • if the ground is bad, dimmer switch needs replacement

EDIT: dimmer switch checks according to the service manual