Just changed both batteries in my 2010 F-250 6.4L diesel and after i replaced the first I had power, when I replaced the second, now i have no power. both batteries where charged.
Did you connect them right. Make sure the polarity is correct.
Yes. talking to the service dept at Ford I blew a fuse because I didn't connect them all a once I disconnected the second Battery in series so I had enough room to get the battery out and when I reconnected it after I connected the first one I blew a fuse.
Glad you found the problem
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