Mrmerlin

turning on the key made the gauge peg, this was without starting the engine

FredR

Stan,

Perhaps I can re-phrase my query:
- when the motor was running did the gauge exhibit any strange behaviour
- when you stopped the motor did the gauge return to the pegged condition? I suspect not the case.

Still having issues myself as per the thread I initiated. Starting to suspect my "new" sender may be duff.

Mrmerlin

Fred, once the key was turned to run or crank the gauge would peg and stay pegged till the key was turned off it did not matter if the engine was running or stopped it was pegged

FredR

Thanks-mine pegs all the time [more or less] when the ignition is off and can drop to zero when the display is nudged. It will then peg when the ignition is switched on and when the motor is fired up it starts to behave more or less normally but can suddenly freeze when the motor is running and then stay put irrespective of revs. Switch off and whatever it s frozen at drops off and then suddenly it will go full scale.

At my wits end with it.

upstate bob

If you have eliminated the sender as the problem then you have a short to ground either on the sender wire or at the gauge.