IH8RUST: FJ60

[IH8RUST]

Going to the cluster gauge, I got voltage on the harness. Oh god, I think it’s the cluster gauge.

 

[RDub]

The connector contacts often oxidize causing the cluster to become a cluster. As you know there are many pins and mating sockets. Mine was acting up and a careful cleaning with de-ox it and mild abrasive fixed it. Worth a try.

 

[IH8RUST]

Lots of debugging, it’s a bad ground somewhere. Now where?

 

[IH8RUST]

The connector contacts often oxidize causing the cluster to become a cluster. As you know there are many pins and mating sockets. Mine was acting up and a careful cleaning with de-ox it and mild abrasive fixed it. Worth a try.

I ended up using wire brush to clean the connectors while I have it pulled out!

 

[IH8RUST]

Sitrep, I'm tired.

Went down the usual rabbit holes first: replaced the dimmer rheostat, replaced the headlight switch, pulled the cluster, and inspected the printed circuit (traces were fine). Meter read ~12V everywhere, so I kept chasing "where's the power going?" That was the trap.

What actually cracked it:

• A DMM will happily show 12V through a dead or high-resistance connection because it draws almost no current. Switched to using an LED as a load tester, and that told the truth: power was real all the way up to the cluster.
• The HVAC illumination was dead too, which meant it wasn't the cluster.
• Turns out it was the GROUND, not power. On these, the panel illumination grounds back through the dimmer. The bulbs had +12V the whole time; they just had no path to ground. Touching the bulb-return pin to bare metal instantly lit the whole dash. Ugh.

Root cause: bad/intermittent ground at the dimmer connector. I'm still unclear why this is happening now. The kicker: the factory rheostat barely dims LEDs anyway, so it was never doing much. I'm trying to convince myself of that much.

I have a couple of fixes in mind:

• Free version: bypass the dimmer and permanently bond the bulb-return wire to the ground wire (solder + heat-shrink). Dash and HVAC come on full bright every time. Yay (?)
• I still want dimming back with LEDs? Need to find a high-side PWM dimmer, but then I have to figure out how to house and mount it with OEM. Breaks my heart not having the knob, so I want to see if I can hack something together.

And for my lesson of the day:

• "Works, then doesn't, same steps" = an intermittent connection, every time.
• Don't trust meter voltage on a loose wire; load-test with an LED or test light.
• Sort out whether it's a power OR ground problem before swapping parts. Giving the circuit its own ground during testing can mask a faulty factory ground.
• Stock rheostats don't dim LEDs, go PWM/high-side. I still don't fully understand why the F the whole thing worked before, and now it doesn't.

 

[IH8RUST]

Installed the new seatbelt from the planet. They’re really, really nice.

 

[IH8RUST]

Before.



Since I have it out, wet sanded with 5000-10000, then used the Chemical Guys V38 with a wool pad to polish the glass. It buffed out most of the hairline scratches, gave it a nice clear shine.

Going to attempt to paint the bezel, waiting on the paint to arrive.