Re: Ford truck fuel gage..empty?
"Lynn Coffelt" <email@example.com> wrote:
>> Use a voltmeter, not ohmmeter, two reasons... it's NOT 12v so not
>> confusing.. mistake can blow your ohmmeter, start at the switch with
>> key on
>> looking for zero to five volts (which is what gage supplies) and the
>> sender grounds it
>> full tank always was near or no resistance (a short) so youre looking
>> at straight five volts until you come to the break in the wire or bad
> Thanks Krusty,
> (Friend thanks too) I think I've got it. The gage sources 5
> volts, and
> the tank sender grounds this through a rheostat (or equivalent), with
> a near zero resistance to ground indicating a full tank?
> Sounds like a possible short to ground somewhere along the path
> the switch to the sender (or maybe the switch or sender themselves)
Now I am confused.. remember, the sender grounds.
In the legacy case, taking the wire off an oil, temp, or gas tank sender
causes gauge needle to drop to 'zero'.. and grounding it sends the gauge
to full or high or hot.. ie, the opposite of no needle movement.
thus you are looking for the source point of a disconnect.. not a
'short'. On the gauge side of the failure point, the wire should read 5
volts. ignore fluctations, if any.
Be aware that some think a 'short' means a break.. in reality, it's
connecting something that shouldnt be connected.
Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!