90 series sub fuel gauge and clock not working

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Guys,
a while back the sub tank fuel gauge and clock for my petrol 90 series stopped working. The switch still switches the tanks over but the green light doesn't come on so i have just been living with it, drain the sub first then the main. Not a big problem with the clock either as i have a watch. But now I am planning a big trip and would like them to work.
When it stopped working i checked the clock and dome fuses and they appear ok. I went to the scrap yard, stuck a working used gauge on but it didn't work either. I found earths seem to feature as common problem with 12v but where are they? how do i test them?

Before i strip out the fuel tanks etc does anyone have ideas as to where i should check or where to probe?

Ben

[StormyKnight Advanced Member Find all posts View Profile Close StormyKnight]

Re: 90 series sub fuel gauge and clock not working

According to my Ellery's, the clock should be the easiest to diagnose...

From the battery the power goes to the 10A Dome fuse using a black wire.
Then to the clock using a red wire - i.e. the clock should have power at all times even with the ignition off. This is so the clock keeps time not so it lights up.
Then the clock has two wires going to earth - a BR (Brown) & a W-BK (a white with black stripe)

The clock also has another two wires for supplying the display power & dimming when the lights are on - a GR-R (Green with red stripe supplies the 12V via the 15A Cig fuse & the other wire without colour (?) goes to the illumination system.

The W-BK cable mentioned above as one of the earths also joins & earths the cigarette lighter - do you know if that works?

Because the clock & subtank gauge are physically very close together, I would strongly suggest that there is an earthing issue as you have suggested.

Do you know how to use a multimeter to test voltages & check for wire continuity?

If you download this PDF I found online, then go down to Clock/Lighter Toyota it gives what I think is basically a copy of what I have in my elleries.

http://www.autoshop101.com/forms/allinone.pdf

Cheers

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Re: 90 series sub fuel gauge and clock not working

Cheers Richard,
I don't smoke so i will check if the lighter works and go from there. I will read through the instructions for the multimeter again before i start tomorrow morning so i don't fry the system, its only a cheap Dick Smith one but I'm sure it will do. Thanks for the help, will report back.
Ben

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Re: 90 series sub fuel gauge and clock not working

well it's working again... i tested the earths, pulled the dash out, the fuseboxes, loom to check the wire colors to see if they had rubbed, nothing After eight hours i couldn't find the problem so decided to put everything back together again :cry: As i put the last connector on it sprung into life... So, i'm very happy but no further forwards as to what was wrong... and glad i didn't have to pay for the privilege.

[StormyKnight Advanced Member Find all posts View Profile Close StormyKnight]

Re: 90 series sub fuel gauge and clock not working

No worries, it may have just been a dodgy connection. I suspect my speedo issue was also as the speedo guy said that he found a connector that came apart without needing to push on the clip.

Cheers