Re: changed frayed connection to oil sender in 22nd series Custom and now not working.

Posted by HH56 On 2021/10/31 17:27:07

What Kev said but on a 48-50 model all the senders most likely will read a short or very low resistance to ground when off and tested with an ohmmeter. The type sender Packard used in those years have a heater element wrapped around a bimetal strip which only opens and closes a contact to work the gauges. Other years use the changing resistance type senders most are familiar with and that type will read between 10 and 75 or so ohms with the meter.

External force (temperature, in this case) working with the sender heater in conjunction with another heater in the gauge all work together to vary the heating action on the bimetal strip in the sender which opens and closes the contact. The frequency and duration of the open and close action as changed by the temperature, oil pressure, or fuel level provides varying length pulses to ground which works the gauge heaters to move the gauge needles.