100 series - Main gauge lights not working (not Rheostat)

[Dazzler79]

Hi all,

I am seeking advice on my gauge cluster lights. I have a 2003 UZJ100 RHD (Australia), and all instruments are working, except for the main Type 74 gauge lamps. I have read through the available threads and checked the following.

-Fuses for gauges, panel light, and tail lights in all 3 boxes - all intact.
-I pulled out the rheostat and tested that. Resistance is in spec, and the roller functions correctly; the circuit is intact. Ground is intact.
-Rheostat cable - correct voltage, the ground is intact.

Looking for ideas on next steps?
- I am thinking of removing the whole cluster and testing the supply sockets and cluster pins.
- A harness for a battery box in the boot was put through the firewall grommet a while ago, I am worried the main loom got snicked slightly.
- Does anyone know if the globes are wired in series or parallel? I'm thinking that if globe 1 is gone, it may knock out the others. It's hard to imagine Toyota doing that, though.

After that, I am all out of ideas. Any others would be welcome!

Cheers.

P.S. I am relatively new to DIY auto repair, but my neighbour is a 30-year Toyota mechanic and can hand-hold when needed.

 

[excessive]

are you getting 12 volts at the light terminals ?

 

[Dazzler79]

are you getting 12 volts at the light terminals ?

Would these be the terminals to which the main Cluster assembly connects? (the sockets the yellow connects too)

 

[Dazzler79]

UPDATE: I pulled the Panel and the Rheostat, and took them to a specialist gauge cluster place here in Melbourne, who very kindly tested them (for free). All working and in good condition.

I generally don't drive this car at night, so I hadn't realised it is not just the panel lights but also the shifter lights, centre dash lights (AC knobs, etc.). This makes me think I should rule out the rheostat ground or positive wires, as some of those lights are not on the dimming circuit (I think, if I am reading the EWD right).

Is there another fuse or circuit that could be affecting this? Checked 7.5A Panel, and Tail fuses again, and swapped with new ones just in case the old were bad but not blown.

In terms of aftermarket mods, I do have a rear bar with additional tail/brake lights that seem to have been spliced in by the installer... this issue presented many months after that install, though. It is a variable I am considering.

Any advice appreciated!

 

[excessive]

is / are anything else unplugged in the interior ? and i do mean anything