John,
The original wiring for the fuel light is: one of the green wires
attached to the A4 fuse terminal goes to one of the terminals on the
lamp socket. Current then goes through the lamp filament and through
about 70 ohms of resistance wire wrapped around the lamp socket to the
other terminal on the socket. From there a green w/black tracer wire
goes to the rear of the car, along the left side of the chassis to a
single bullet connector. From there another wire (ideally green/black)
goes to the terminal on top of the low fuel warning switch. When the
fuel gets low a contact inside of the switch gets grounded to complete
the circuit and illuminate the bulb.
Your 'always on' symptom would lead one to suspect that the green/black
wire is shorting to ground on its way back to the switch. Or, that the
fuel warning switch is stuck in the grounded position. Checking the
switch is fairly easy. Go under the back of the car and locate the
'petrol tank unit'. The wire should be going to a terminal on top of
the exposed portion of the unit and is held in place by a bakelite thumb
nut. Remove the wire. Does the light go out? If so, and there's more
than about three gallons of gas in the tank, the unit is stuck in the
closed position. That'll require removing and replacing/refurbing the
unit.
If the light doesn't go out with the wire removed from the unit, the
green/black wire is shorting to ground somewhere between the lamp socket
and the back of the car. That's a matter of tracing out wires until you
find the culprit
If tapping on the dash can cause the light to go out, you may have a
loose screw connection at the lamp socket.
Hope this helps.
Bud Krueger
52TD
Plymouth, MA
Gunnell, John wrote:
>Good Morning
>
> Weather hasn't been the best for MG'ing in central Wisconsin, but my son
>and I did get to the Fox Cities British Car Club spring "wash Up/Tune Up" in
>Appleton last Saturday. It was a brisk 120-mile R/T. Good event. 38 cars
>including my TD, a much nicer TF, a Nash Healey and a Lotus 7.
>
> Noticed my fuel monitor light is on all the time this year. It was doing
>that when I first got the car 1-1/2 years ago, but then if I tapped the dash
>it went out. Last year it never came on at all (and I did run dry one time).
>This year it's on all the time. Looking for possible causes and fixes. I'll
>bet there's a million. The car was rewired by DPO and as far as I can tell, he
>did a nice job.
>
> Another note, our new Standard Guide to British Sports Cars went to the
>printer on Monday and should be out soon. Some of you might be interested.
>
>John Gunnell
>Old Cars Weekly
>Iola, WI
/// unsubscribe/change address requests to majordomo@autox.team.net or try
/// http://www.team.net/mailman/listinfo
/// Archives at http://www.team.net/archive/mg-t
|