Hi, this is my first post here...

So I just installed a new alternator on my 89 Accord. I started it up to let it run for about 5 minutes, all good... Sounded fine. When I went to turn it off, I took the key out of the ignition, and nothing stopped! Even the headlights and radio work when the key is completely removed. So I went to call someone who might help me, but they weren't there. When I went back to the car, there was steam coming out of the radiator, near the cap (it was coming out the side into the engine area).

Not knowing what else to do, I unplugged the battery.

And here I sit, not knowing what I've done.

Any advice?

 

Suggest a faulty ignition switch assy. Probably cause of your original problem instead of alternator.

good luck

 

could be the switch, but if it didn't do it before and the alt was replaced with a correct diagnosis...it may have a faulty diode letting current feedback through the ignition system keeping the car running...it happens.