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So my alternator on my 72 350 went bad. I went and got a new one. I hooked it up and the plug is different. They gave me a new plug that will fit, I just have to change over the wires. I just don't know which way the wires are supposed to go! Can someone help me out?
This is the new alternator plug next to original plug:
This is the new plug replacement:
This is the old plug next to the new alternator:
Is it still the same orientation? Has anyone ever dealt with the before? I don't want to fry my car!!
Any input would be appreciated. Thank you!
They gave you an internally regulated alternator and your original is an externally regulated alternator with the regulator mounted on the firewall. You have some extra wiring work to do if you want to use your new one.
The first question is, what style alternator did you get? The 1972 cars used the oddball externally-regulated alternator in a case that looks like the internally-regulated alternator. I guarantee that no parts store listing gets this right.
The new alternator is an internally-regulated 12SI style. Does your car have a voltage regulator on the firewall? All 1972 Oldsmobiles did from the factory.
This is also a teaching moment to never return a core until you are absolutely sure the new part is identical.
And is why I like to get what I have rebuilt locally if at all possible.
Take it back and show the store manager the pics of your plug vs the alternator you were sold. Ball's in his court then.
You can make this work as there are voltage regulator bypass harnesses available for this very changeover. I don't see the need to go thru the expense and aggravation to rectify their mistake.
The fact that the store gave you a plug and said to change it proves that they are completely clueless. If you plug that alternator into your stock wiring with the external regulator, you will likely damage the new alternator. Of course, then it will be your fault.
WOW! Thank you everyone for your help and insight to someone who is good with wrench but not with know-how. I went and got the right alternator, after going to three different stores, and got the right thing. The reference photos really helped.
Thank you all for your help!! I sincerely appreciate it.
May 28th, 2021, 03:46 PM
