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Discussion Starter · #1 ·
I have a VDO fuel gauge and I don't know what ohm it is so I can purchase the correct sending unit. Can anyone tell me how to find out what ohm the gauge would be? I have the part # off of the gauge but can't find it anywhere on the net. Sure would appreciate some direction.
 

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Yes, I did search VDO site and could not find any info. I also completed their online form for an answer but haven't heard back. I did not purchase the gauge. It was in the car when I bought it. I think this gauge must be discontinued because I can't find the part no. on their site.
 

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This is JUST an idea ...:pimp:

Could a guy ("a guy" being you) get your hands on any kind of rheostat?

I'm thinking of the type on a headlight switch or dash panel lights dimmer.
Better yet ... a fuel tank sending unit out of an old chevy!:D

If you attach B+ (12V) to the appropriate side of the guage, and then wire in the rheostat on the the ground side of the guage (The wire that goes to the fuel tank sender)

Begin by rotating the switch to the fully dimmed position before connecting any current. You should should show an empty tank. Slowly rotate the rheostat, and watch for the needle to move. Using a multi-meter, test and record the resistance value at this point as your MIN Ohms. Continue turning the rheostat in very small increments, pause, and watch the needle on the guage rise. When it hits the "Full" mark, test and record the resistance as your MAX Ohms.

A typical OEM GM guage should be a 0-90 Ohm. Some Ford and Chysler operated in the 10-80 Ohm, many iports were much higher.
 

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Discussion Starter · #8 ·
This is JUST an idea ...:pimp:

Could a guy ("a guy" being you) get your hands on any kind of rheostat?

I'm thinking of the type on a headlight switch or dash panel lights dimmer.
Better yet ... a fuel tank sending unit out of an old chevy!:D

If you attach B+ (12V) to the appropriate side of the guage, and then wire in the rheostat on the the ground side of the guage (The wire that goes to the fuel tank sender)

Begin by rotating the switch to the fully dimmed position before connecting any current. You should should show an empty tank. Slowly rotate the rheostat, and watch for the needle to move. Using a multi-meter, test and record the resistance value at this point as your MIN Ohms. Continue turning the rheostat in very small increments, pause, and watch the needle on the guage rise. When it hits the "Full" mark, test and record the resistance as your MAX Ohms.

A typical OEM GM guage should be a 0-90 Ohm. Some Ford and Chysler operated in the 10-80 Ohm, many iports were much higher.
I have no idea. No, I do not have a sending unit. Met a guy at a recent car show who bought a 0-90 sending unit for his car and it didn't work. He offered to sell it to me at a reasonable price but I don't want to be in the same boat. If I can't figure it out I guess I can just buy a new fuel gauge. I still haven't heard from VDO.
 

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The numbers on the gauge are 301280001 and 121003477
It does appear that VDO fuel gauge part numbers ARE in the format "301 999" or "301 999L " ... (with "9's" being Digits from 0-9, an "L" being Characters from A-Z)

I was also able to find them in the same format as you posted in a "Continental VDO" PDF catalog.
See the numerical index on PDF page 95.

Nothing that matches the number that you posted, though.
Perhaps it has been discontinued or superceded?
Try contacting VDO directly?
 

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Discussion Starter · #12 ·
I'm not sure if you caught my idea or not.

The premise was to use a rheostat of almost any kind, so that you could test the guage and measure the min and max Ohm ratings using a multimeter to DETERMINE the range.
Yes sir I did and I will try that. Thank you for that great idea. Also want to thank you for doing that leg work. I did contact VDO vie their website but could not find a number to call. I have not heard back from them. Right now the car is in the shop getting an a/c installed amongst some other things. It should be out Friday so when I get it back I will try that.
 
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