Looking for skilled electrical help, I'm clueless

[Koenigturbo]

Hey everyone, I'm looking for help for a small electrical problem:
I replaced the light for the oil gauge with a larger bulb, a 194 instead of the #74 that in was in there. I had to cut into the circut board, as you guys know, I had to drill out the hole for a #194 bulb, now the contacts on the socket no longer touch the circut board,(because the socket is bigger) so I tap in power from the old boost gauge light socket, since the new boost gauge has it's own light.

Problem: I bench tested the gauge pack, I hooked up the gauge pack to a battery, all the lights work even the modified #194 bulb, I have current to the wiring harness to the correct corresponding terminals to make the lights work, I checked the fuse's, and reset the breaker, all good. I plug in the gauge pak to all the harness, everything works except for the lumination for the gauges. Why won't the lights work when I plug it in the car, but it will work when I bench test it?? Dimmer shot??

Dimmer test: I tested the dimmer, it won't go past 3 volts nor will it drop to zero volts when I turn the dial. The green wire reads a full 12 volts, and so does the white/green wire, the white with black stripe wire reads no volts, why would you get two wires reading 12 volts? also why would the test light be bright on the green wire and very dim on the white/ green wire when they both read 12 volts??

Thanks Again!!!

"Electric dummy"

 

[Nick M]

Current.

I can't say I ever had to pull the gauge out. Or drill on a customers combination meter or circuit board. Have you checked the EWD or repair manual diagnostics to see how high the dimmer is supposed go?

 

[SupraMan1987]

Could have almost no amperage on the white/green. Are you sure your grounding is good? I tried looking for the diagram of how it worked, but electrial diagrams from the online TSRM are a pain in the ass at best.

 

[Evilempire1.3JZ-GTE]

I think the dimmer goes from 0 volts to 3 because it dimms the lights by changing the ground refference hold on while i check.

 

[Evilempire1.3JZ-GTE]

Ok this is how the supra dimmer works.

Its called a Light Control Rheostat.
It haves three wires that feed ground, power, a biased ground side output!

The green wire feeds it +12VDC
The white black wire feeds it ground 0vdc
The white green or green white wire feeds the biased ground or center tap of the pot

so it making 0-3 VDC sounds about normal it applys 12-9vdc to the lighting by varring the ground side.

Here is what you want to do!
screw the light bulbs.
Buy a blue or white 12vdc car interior lighting led kit it comes with 12vdc leds or a set of leds and and resisters you put one resistor in series with the led if the kit comes with them.

To do this right you want to do a dimmer mod! cut the green wire out of the dimmer cap and stow the wire cut it flush make sure it doesnt touch anything.
splice the white/black wire to the green/white or white/green then you could remove the dimmer or leave it in wont matter it fixes your lighting system at full bright or 12vdc.

Its better to do this because LEDS hate to be dimmed they are either on or off

 

[Koenigturbo]

Ok this is how the supra dimmer works.

Its called a Light Control Rheostat.
It haves three wires that feed ground, power, a biased ground side output!

The green wire feeds it +12VDC
The white black wire feeds it ground 0vdc
The white green or green white wire feeds the biased ground or center tap of the pot

so it making 0-3 VDC sounds about normal it applys 12-9vdc to the lighting by varring the ground side.

Here is what you want to do!
screw the light bulbs.
Buy a blue or white 12vdc car interior lighting led kit it comes with 12vdc leds or a set of leds and and resisters you put one resistor in series with the led if the kit comes with them.

To do this right you want to do a dimmer mod! cut the green wire out of the dimmer cap and stow the wire cut it flush make sure it doesnt touch anything.
splice the white/black wire to the green/white or white/green then you could remove the dimmer or leave it in wont matter it fixes your lighting system at full bright or 12vdc.

Its better to do this because LEDS hate to be dimmed they are either on or off

These bulbs are already L.E.D."s they have resistors already built in. everything is correct, polarity, everything. As i said it works just hooking up battery to it, (Off the car, on the bench) when I plug the gauge pack in the car and turn on the switch, the gauges work, just the Lights don't work,
It was all working before, all I did was switch from a High powered L.E.D. to a Hight powered 360 degree beam L.ED.
My thoughts; The repair manual says it should zero volts when the dimmer is off. It reads three volts all the way "on" how does three volts run the L.E.D."s shouldn't it take about 12 volts to feed all four L.E.D."s?

question: green wire and white/green reads 12 volts, why would white/green be really dim on the test light and really bright on the green wire should they both be bright since they read 12 volts? also, when I dial the dimmer all the way down it reads voltage, very little, lees than a volt.
guage lighting: works when its on the "bench"
doesn't work when you plug it in the car....

 

[Evilempire1.3JZ-GTE]

You need both voltages to work your dimmer needs a ground &12vdc input the dimmer setting is the green white output.

Your gauge lights are not working because your not getting the ground but since you have 12vdc input dont matter what setting you put your dimmer at you have 12vdc.

You might even notice the gauge lights come on a little bit when you hook the test light up because it will get a ground through the test light.

Just ground that green/white wire coming out of the dimmer then all your gauges will have 0 & 12vdc and be on full bright.

hook up the led from there the correct polarity and enjoy!