Fuel Gauge stopped working

Submitted: Tuesday, Jun 29, 2010 at 17:51
ThreadID: 79729 Views:4887 Replies:4 FollowUps:1
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Hi all

The rear tank fuel gauge has suddenly stopped working in my 75 series Troopy.

The voltage measured at the rear of the gauge is only 5.5v even though the tank is full, I am guessing that it should be 12.0v for a full tank?

Can anyone offer suggestions of where I should be looking, or what the possible fault might be.

Thanks in advance for any info.

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Reply By: Member - John and Val - Tuesday, Jun 29, 2010 at 19:27

Tuesday, Jun 29, 2010 at 19:27
The sender unit in the tank of my old 75 series is simply a spiral wirewound resistor with a float operated contact that runs along the resistor to provide the output voltage. Don't know what the voltage should be - that would be decided by the gauge, but probably not as simple as 12V. In mine the resistance wire broke in the middle, the gauge read full for over half, and empty for under half full.

If your problem is the sender unit, suggest the best fix is to replace it. I actually repaired mine by replacing the broken resistance wire, but that was because I had suitable resistance wire and was interested to see if it was possible. It was possible, but it's not something I'd recommend to anyone with finite patience and time!

If you drop the tank from the vehicle (empty it first) and remove the sender assembly, you should see any obvious damage there. Unless your problem is that the gauge shows only full and empty, I think I'd explore other possibilities first.


J and V
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AnswerID: 422501

Follow Up By: Michael46 - Tuesday, Jun 29, 2010 at 22:10

Tuesday, Jun 29, 2010 at 22:10
Thanks John

It is reassuring to hear from someone who has had the same problem and managed to fix it.

FollowupID: 692916

Reply By: Member - Alastair D (NSW) - Wednesday, Jun 30, 2010 at 07:39

Wednesday, Jun 30, 2010 at 07:39
Had the same thing happen recently in my 75ser Troopy and it was the sender unit. The resistance wire had worn through and the pickup had snagged at about mid way. Replaced the sender unit and all is well. Cost was about $200 for a third party unit which was a better design than the original. Lasted 380,000 - wonder what the new one will do?

AnswerID: 422544

Reply By: Member - Shane D (QLD) - Wednesday, Jun 30, 2010 at 14:49

Wednesday, Jun 30, 2010 at 14:49
Try to take the wire off the sender unit and earth it out, you will need some one to watch the gauge in the dash with the ignition on, If the gauge goes to full by doing this, you will then know that it IS the sender unit,

AnswerID: 422589

Reply By: Michael46 - Wednesday, Jun 30, 2010 at 21:46

Wednesday, Jun 30, 2010 at 21:46
Thanks for all the replies, looks like I will be replacing the sender unit.

AnswerID: 422641

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