Thanks for the help and i have another question. I have 1955 Ford car shop manual however it dosent have a good illastration of the wiring diagrams? It shows the red-green tracer wire from key to coil never showing the Starter relay in the diagram? So my battery should be Positive to ground and negative to starter relay?

Asked by Jul 02, 2012 at 11:04 AM about the 1955 Ford Thunderbird

Question type: Maintenance & Repair

3 Answers


Your 1955 Ford is 6-volt POSITIVE ground. I never understood why Ford did that but Anyway, Here is an excellent article that should explain any and all of your questions in rewiring your Bird. Just paste this link into your browser Kenny / MrBlueOval.

2 people found this helpful.

If you are keeping your 'Bird 6 volt, then yes, the positive goes to ground, the negative is switched. Technically, this is correct; when current flows from a battery it actually flows from negative to positive. However, we have been taught from the beginning that current flows positive to negative, hence the confusion. Not much difference really; just be sure that when you replace a voltage regulator you mention it is positive ground. The coil terminals are reversed also, the negative attaches to the power supply and the positive goes to the distributor to the points... bulbs it makes no different, starter and relays work the same, heater fan motor the same. Radio must be a positive ground unit. If you are switching to 12 v neg ground, use a one-wire alternator, use a drop down resistor for the heater fan, or replace it with a 12 v unit, replace the coil, and rewire negative to the points. You'll have to use a drop down resistor to the gas gauge, or replace it with a 12v unit. Many 'Bird restoration sites offer 12 v conversion units...

3 people found this helpful.

When you convert a 6V positive ground system to 12 negative be aware that the original radio will never work again.

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