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John Pizzi - Squarebirds Administrator
Thunderbird Registry #36223
jopizz@squarebirds.org 856-779-9695
https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm -
When I pulled the wire from the Gauge and I just grounded that wire only, the gauge went to 3/4 and the test light I was using as a ground wire (I figured it was just a wire passing through a light more or less) was flashing, as if the connection was good from the tester to the gauge and back to test light, I thought.
My temp gauge works so we know the CRV or CVR thingy is good up there under the dash.Comment
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I wasn't aware you were just rehashing what you did previously. When you get around to replacing the wire tomorrow or whenever as I suggested let me know the results. If it's just a bad wire from the harness to the sender that's easier and cheaper to fix than the sender.
JohnJohn Pizzi - Squarebirds Administrator
Thunderbird Registry #36223
jopizz@squarebirds.org 856-779-9695
https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htmComment
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John Pizzi - Squarebirds Administrator
Thunderbird Registry #36223
jopizz@squarebirds.org 856-779-9695
https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htmComment
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Remove the fuel tank sending unit. No need to replace wires yet.
Once you get the float assembly out, the whole picture will become clear. It is a variable resistor that should measure ten-ohms when the tank is full and 100-ohms when empty.
Using a test light in series with ground is good. It proves two things; how consistent and steady the flashing occurs and the simple fact that your wiring has a complete path from the dash to the tank.
Mechanical CVRs work like your turn signal unit but they are on at all times your key is on. They should output a STEADY 12-volt pulse, 50% on and 50% off. This averages the current to a 6-volt system. When mechanical CVRs get old, the flashing gets erratic because the contacts get pitted and burned. Old CVRs can also stick ON (all the time) or burn open. - DaveLast edited by simplyconnected; July 10, 2018, 07:08 AM.Member, Sons of the American Revolution
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From: Royal Oak, MichiganComment
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When I did what you said above I did get a steady consistent flash that was not erratic.Comment
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John Pizzi - Squarebirds Administrator
Thunderbird Registry #36223
jopizz@squarebirds.org 856-779-9695
https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htmComment
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As I explained last night, where my wire goes into the take there is a black rubbery substance or some soft substance, I assume I need to pull that out to get to the top of the sending unit which will not hurt anything, just expose the wire connection to the sending unit. Has anyone seen this before, will I need to put the same thing back in when I put another sending unit (I am putting my money on that being my issue when I get home and test the wires with a new wire).Comment
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That was just a sealer to prevent water from getting into the unit. Usually it's soft enough where you can reuse it. If not rope caulk or something similar will work just fine.
JohnJohn Pizzi - Squarebirds Administrator
Thunderbird Registry #36223
jopizz@squarebirds.org 856-779-9695
https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htmComment
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I disconnected the wire from gauge/harness from the wire going into the tank. Put a wire between them, same result, stays at 1\4 level.
I plugged the wires back up and grounded at the place where the wire goes into the tank (I removed some of the black goo to get a good clean shiny metal surface) and grounded to a good place in truck, several places to confirm same results, every time the gauge pegged out to full.
I am thinking bad sending unit.Comment
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just for grins, the harness from the guage that comes into the trunk on the drivers side, I giggled it, moved it around, so see if maybe a short was there, nothing changed, so I guess wires are good? I looked at them closely, it all looks nice and clean, I pulled some of the orig factory covering off of them and all seemed in great shape. Nothing pinched or the like that would make you think could be an issue.Comment
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I disconnected the wire from gauge/harness from the wire going into the tank. Put a wire between them, same result, stays at 1\4 level.
I plugged the wires back up and grounded at the place where the wire goes into the tank (I removed some of the black goo to get a good clean shiny metal surface) and grounded to a good place in truck, several places to confirm same results, every time the gauge pegged out to full.
I am thinking bad sending unit.
JohnJohn Pizzi - Squarebirds Administrator
Thunderbird Registry #36223
jopizz@squarebirds.org 856-779-9695
https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htmComment
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