HILLMAN CAR CLUB
OF SOUTH AUSTRALIA INC

Tech Tips:  Finding Gauge Faults
Is the fault in the gauge, in the sender,
or in the wire between them?
HILLMAN CAR CLUB
OF SOUTH AUSTRALIA INC



From: Bill Atkin [elderfuthark(at)yahoo.com.au]
Sent: Monday, March 14, 2005 11:35 AM
To: HillmanCars@yahoogroups.com
Subject: [HillmanCars] Bills update

Team

1) Evelina is now purring with a new motor and tune.  Thanks to Simon.  I am in hillman heaven and have taken her for ever longer adventures listening to that beautiful deep note.  Now I need to fix/replace my fuel gauge so I have a chance of getting home again.  Connected to the sender and to switches but no signal.  How do you test a fuel gauge?

... (snip) ...

5) SWMBO now believes I am not the craziest because she has met people with more rootes cars than we have.

cheers

Bill



From: importautosbdo(at)juno.com
Sent: Monday, March 14, 2005 3:09 PM
To: HillmanCars@yahoogroups.com
Subject: Re: [HillmanCars] (Bills update) Fuel gauge

Fuel and temp gauges (except perhaps the new stuff tied into the computers) are a very simple circuit: They get power from the ignition "hot" side, usually (but not always) going through a voltage stabilizer; and are grounded through the sending unit.  You need make sure one lead coming in has power 9 to 12v.  Disconnect the other lead, the one going to the sending unit.  This should peg the needle at one end.  Connect a wire to this connector, and ground it.  This should peg it at the other end.  (Probably not good to leave it fully grounded for longer than necessary to watch the needle move. If it does.)
If you get full deflection on the gauge, it's OK.  Next step is reconnect the sending unit wire, and go to the sending unit itself.  Do the deflection text again: from disconnected to grounded should give you the full range on the gauge.  If it tested OK at the dash but not at the sender, you have a wiring problem somewhere between.  If it does work the gauge from the wire but not the sending unit, the sending unit is probably bad.  In the case of a fuel gauge, you can take out the sending unit, hook up an ohmmeter between the lead going to the gauge and the mounting plate of the gauge (or the other wire, if it has a grounding lead), move the float arm and watch the ohmmeter.  If the resistence doesn't change, the sender is bad.
Linden

From: Jan Eyerman [jan.eyerman(at)usa.net]
Sent: Tuesday, March 15, 2005 2:32 AM
To: HillmanCars@yahoogroups.com
Subject: Re: [HillmanCars] (Bills update) Fuel gauge

Older Hillmans do not have a voltage stabilizer, the gauge is wired to measure the difference in voltage between the battery and ground and the battery and the sending unit.  Interesting set up, but absolutely requires a good ground for the gauge.

Jan Eyerman



From: Bill Atkin [elderfuthark(at)yahoo.com.au]
Sent: Monday, March 21, 2005 7:30 AM
To: HillmanCars@yahoogroups.com
Subject: [HillmanCars] Re: Evie goes to Bendigo

Just thought everyone would like to know that Evie and Bill drove to Bendigo and back from Melbourne on one tank of petrol (7gal) without running out because the fuel gauge WORKS!  Thank you for your advice.  The critical factor seemed to be using a direct ground to the battery.
... (snip) ...

cheers

Bill


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