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After a storm, I started my truck and it showed error. 3 where the miles are and the speedometer goes to 85 anytime the truck starts moving. I have tried to recalibrate it by using a clip in the single pin connector under the dash and putting in the new speed constant. I used one of the six calibrations I have and it did not work, I'm scared to do it again because I do not want to waste them. Any other ideas I can check for? Could this be from water damage?
Is it a 52 Packard?
Use the appropriate service manual for your truck and do what it says for your speedo inop
Do the pinpoint tests
Those pinpoint tests will not say to recalibrate for a missing speed sensor signal or a power and ground issue
Use only the Ford books or use AllData for the testing procedures