Re: 6 to 12 volt conversion
Posted by HH56 On 2020/3/25 16:07:06
One thing those early 50s Packards are somewhat prone to is corrosion and rust affecting grounds to the various bulbs. Make sure there is a good ground at each bulb housing before totally blaming something else for the lack of signals.
One thing to check is the type of modern 12v flasher to make sure the pinout is identical to the old 6v style. Many of the new flashers are differently constructed so pin locations and functions are different. If you can find an original thermal style flasher for a 1955-56 model that one should plug in and work. If a new replacement flasher is all or part solid state, going negative ground should not be an issue with those as far as polarity. Trying to convert if the ground stays positive is more of an issue. Part solid state flashers usually will work the outside lights because those bulbs stay on a thermal contact setup. The dash indicator light(s) on some partial solid state modern flashers use a transistor to work them and that needs to have the transistor be designed to work with the cars ground polarity as would a full solid state unit.
Here is an extraction of the turn signal circuit showing the pinout of the old thermal style flasher and how the rear turn signal filaments get their brake and signal power thru the switch.
Attach file:
(213.91 KB)
One thing to check is the type of modern 12v flasher to make sure the pinout is identical to the old 6v style. Many of the new flashers are differently constructed so pin locations and functions are different. If you can find an original thermal style flasher for a 1955-56 model that one should plug in and work. If a new replacement flasher is all or part solid state, going negative ground should not be an issue with those as far as polarity. Trying to convert if the ground stays positive is more of an issue. Part solid state flashers usually will work the outside lights because those bulbs stay on a thermal contact setup. The dash indicator light(s) on some partial solid state modern flashers use a transistor to work them and that needs to have the transistor be designed to work with the cars ground polarity as would a full solid state unit.
Here is an extraction of the turn signal circuit showing the pinout of the old thermal style flasher and how the rear turn signal filaments get their brake and signal power thru the switch.
Attach file:
(213.91 KB)
This Post was from: https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?post_id=220417