Fuel gauge not working

[poorpeet]

Flushed with success at getting the heater fan working (Thanks Spend) I have decided to tackle the fuel gauge which has been dead for a while.
Starting at the sender & with the ignition on, none of the four wires is live.
Can anyone tell me what the four are for? (Apart from earth, I managed to work that one out myself) The remainder are Green/black, Red/green & solid blue.
I'll then have a go at tracing them.

[gadgit]

You may be confused to know really what the wires are for? that may sound stupid, but according to the bible they are/

Green/black ..fuel gauge to fuel tank. Of some use!
red/green.....lighting switch to side and tale lamp fuse?
red/light green..windscreen wiper motor to switch ?
blue..........lighting switch to dip switch?

I bet that helps/ I'd say obviously the green black is worth a test.
Otherwise, just replace the tank sender and work from there first.

I'm not an electroncs expert by any means, it may be fed from the lighting switch live side.

Hopefully a smartarse will be along to help shortly???

Good luck, I'm looking forward to some more input as well now!!!

(nice colour Chimaera poorpeet) nearly as nice as mine!

Edited by gadgit on Tuesday 25th September 20:02

[Ribol]

poorpeet said:

Starting at the sender & with the ignition on, none of the four wires is live.
Can anyone tell me what the four are for?

Do you have a low fuel warning light at all?

[spend]

Check the colours:

Green is the feed to all the instruments (should be stabilized but isn't).
Black is the ground (for instrument & lighting)
Red/white is the lights.

To the Tank sender/warning are:
Blue (common)
Green/black(tank gauge)
Red/Black (low level warning)

Well thats what I wrote on my wiring diagram anyway

Dave

[poorpeet]

Nope no fuel level, no low level light, nothing.
If the other to are the signal wires, then the blue should be live? right?
So all I need to do is trace back to find the break. Does the gauge and level light get its power via the signal wires?

[E2DJH]

Ribol said:

Do you have a low fuel warning light at all?

I don't have one of these on my '98 450.
Should i?

[K4TRV]

poorpeet said:

Nope no fuel level, no low level light, nothing.
If the other to are the signal wires, then the blue should be live? right?
So all I need to do is trace back to find the break. Does the gauge and level light get its power via the signal wires?

You probably need to trace back from the gauge to where your Alarm is or was sited (my '93 Chim had a replacement alarm unit in the dash over on the left on top of the relays/distribution unit).

The fuel guage in early cars was wired through the alarm/immobliser - that is if you switch on whilst the immobiliser is still on, you will get zero reading on the fuel gauge - something to do with persuading the potential thief that you had no fuel in the tank!!

You could run wires direct from the tank sender to the gauge to see that all was well ??

I'll have a look at my old records of wiring bits later this evening.

Trev McM

[spend]

Where are you looking at the wires, by the sender, or at the gauge. I would guess you need to make sure that none of the connectors have popped off the back of the gauge (and they are in the correct positions). I have a diag of the layout of my 93 dash (viewed from the back) at http://tvr3.dspen.com/Wiring_Diags/Dash.pdf which may help, ignore my extra gauges & leds they are not standard.

Dave

[poorpeet]

I'm only looking at the sender & moving forward. All was fine until I took out the battery a while back. Since then the fuel gauge has not worked & the car has not been driven.
I think I must have either broken a wire or pulled a connector.
I dont want to disturb the dash until I have ruled out problems with the easier to access wiring.
Thanks for the diagram I'll pin it into the bible.

[spend]

Since neither the gauge (rheostat so in & back to gauge) or the low fuel (switched to gd) are live I suspect your gauge isn't either. It uses the same live as the rest of your dash, so a peek under the cover would be my first port of call.

Note that this is an early car with the black rimmed ETB instruments, later cars had different instruments with other 'features'. I know when its cold outside so I'm happy to be warned to fill the tank

Dave

[poorpeet]

Dash off it is then.
Thanks again for all the help.

Pete