Packard Forum Index » Pre-War (1899-1942)

I have a 1938 Packard, 1601 Series, 4-dr, straight 8. My questions concern the headlight switch.

What is the purpose of the thermostatic relay on the switch?

Also, are there 2, 3, or 4 positions on the switch? Mine is froze up and I'm considering using a universal switch in its place.

Any info would be helpful.

It would help to post a picture of the switch you have now, as I don't think there is a relay incorporated in the 38 switch, also there were 2 different switches that kinda sorta interchanged, one with the fuses lengthwise, and the other the fuses are crosswise. In either case, I think it better to replace with a correct switch, as it is kinda the core of the underdash wiring...

Not familiar with those switches, but is dienes perhaps refering to a circuit breaker?

Looks like Packard used a variety of terms for a circuit breaker. Thermostatic switch, thermostatic overload relay are used in 38 manuals. On 39 switch, it appears to only protect the headlights.

Since switches are interchangeable though, if needed maybe even a later 39 switch could have been installed in service on earlier cars.

Looking at the wiring diagram, I would agree with flackmaster. Very important distribution point and would almost need the proper switch to avoid a butchered rewire job.

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As far back as the early 30s and perhaps earlier Packard used a thermostatic circuit breaker on the headlight circuit.

If you are talking about the round resistor coil (usually at the front of the switch), it is controls the dash light brightness when the knob is turned.