77 F150 auto 6 cylinder starting problems

Asked by Jun 10, 2013 at 11:37 AM

Question type: Maintenance & Repair

I tried the positive cables connected to the pos of batt to the solenoid
when i connected the neg cable my alternator started running?  why is that .

6 Answers


It probably means that you have bad diodes in you alternator.

whats a diodes?


They are an electronic device that only allows voltage to go only one way so a voltage feedback won't happen. I your case it sounds like a complete failure.

Does anyone has another suggestion ... Any other solutions ? Does that mean I have to get a new alternator?


Yep, and you better replace the regulator also. Fortunately the older Ford alternators are very reasonably priced at your local parts store. I am guessing that you have either a 30 or 40 amp alternator as you only have the 300 cid 6 cylinder engine.

I also tried the positive cables to 2 sides of the solenoid and finally thr truck started.. someone mention if this is the case then I should have a ignition or safety switch issue...?

Your Answer:


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    Tom Demyan
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