1956 400 Instrument Panel Lights

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Phantasmcuda
Posts: 5
Joined: Mon Feb 04, 2019 7:05 pm

1956 400 Instrument Panel Lights

Post by Phantasmcuda » Mon Feb 04, 2019 7:19 pm

Hello, I recently purchased a 1956 Packard 400.
All Exterior and interior electrical components operate with the exception of the dashboard instrument panel lights. Interior lights operate when the headlight switch is turned counter clockwise. Head lights and parking lights operate when switch is pulled. Blinker lights work, high beam light works on the instrument panel. However, the instrument panel lights that illuminate the gauges, speedometer, and clock to not function. At a glance it appears all wires are connected and all fuses are working properly.. Any ideas or help will be greatly appreciated. Thank you!!!

Howard56
Posts: 1117
Joined: Mon Dec 24, 2012 11:35 am

Re: 1956 400 Instrument Panel Lights

Post by Howard56 » Mon Feb 04, 2019 10:15 pm

If the rheostat is getting power via the small jumper connected to the tail light terminal then the most likely problem is that the wiper contacts at the center of the rheostat have oxidized and are no longer making good contact. That is a somewhat common occurrence with the 51-56 switches particularly if the car has sat in a moist climate with the switch unused for a long period. Another common area of failure is at the rivets holding the terminals to the ceramic base. Those are part of the electrical path and if the terminals have been pulled and twisted when disconnecting the wires the rivets can loosen and oxidation may develop between the rivet ends and the other metal parts of the terminal assys. If that has happened cleaning the oxidation and restoring function may be short term as it seems any cleaning will not last too long before the oxidation under the rivets is back.

Here is a photo of a 55-6 switch showing the power connections and another of a disassembled 51-4 switch showing where the problem usually happens. Except for details in the dash mount and shaft end where the knob attaches, construction wise the switches are identical so the 51-4 photo is applicable to 55-6. You can try some contact cleaner with the switch in place and that may work but the best way is to remove the switch and thoroughly clean and work the contacts as the contact cleaner is sprayed in.
Attachments
51-4 Headlight switch Exploded view.jpg
55-6 headlight sw.jpg

Phantasmcuda
Posts: 5
Joined: Mon Feb 04, 2019 7:05 pm

Re: 1956 400 Instrument Panel Lights

Post by Phantasmcuda » Tue Feb 05, 2019 9:26 pm

Thank you! The photos are a great help! I'll try testing the switch

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