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1929 chrysler 75 fuel sending unit

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I am working on a 1929 chrysler 75 roadster and need to install a fuel sending unit.  I do not have an original but figured I could install an aftermarket if I knew the ohm range for the Chrysler 75.  So that brings me to the question, does anyone know the ohm range for the 1929 Chrysler 75?


Thank you for any help,



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Hi John,

I checked my gauge by removing the wire from the sender and replacing it with a decade box (selectable resistor) to the chassis and recorded the following.

Short to frame - Full (needle on stop)

10ohms - 1 division over 3/4

20ohms - 2.5 divisions over 1/2

30ohms - 1 division over 1/2

40ohms - 3 divisions over 1/4

50ohms - 1.5 divisions over 1/4

60ohms - 1/4

70ohms - 3 divisions over E

80ohms - 2.5 divisions over E

90ohms - 2 divisions over E

100ohms - 1.5 divisions over E

110ohms - 1 division over E

120ohms - Empty (needle on stop)


Hope that helps





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I have a question for you. My Desoto has been updated to 12 volts. Will I damage anything by hooking up the fuel gauge? 

Does anyone make a 12 to 6 volts step down transformer for cars?  I'd like to hook up the heater again.

I'm not the one that did the 12v conversion. 

Edited by Fossil (see edit history)
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I would think that the gauge would be damaged by 12V as it it. You may be able to limit the current flowing through the gauge to the same values required at 6V by adding a resistor of a suitable value in the circuit. 

You can buy 12V DC to 6V DC (dc to dc converters) but you would need to check out how much current you intend to draw through it as they can only deliver to their rated output. 


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