Jvblakeman

It doesn’t automatically mean the alternator is bad. I would hook up a voltage meter and see if there is any fluctuation, with that. I would also just wiggle the tach wire at the alternator.

My tachometer hooks directly to my alternator, but it didn’t work with the new alternator, that why I went back to my old one.

Let me say...... GET YOURS REBUILT. This summer, mine went out. I went to USA 1 battery and ordered a new one ($529) and gave them my old one. Brought it home and hooked it up (had to make a new bracket, since it wasn’t identical). It didn’t work..... wasn't charging. So I called them and they said to hook up a wire to excite it (previous one was self exciting) I did that, and it was charging, but no tachometer. I went back and asked for my core. They said they already sent it with the core guy. I told them to call the core guy, and get mine back. 1/2 hour later, they “found” mine. I brought the one back that I purchased, and they gave me a full credit. I then took MY core to an alternator shop, where they replaced the voltage regulator, and one bearing. $75 later, I had a perfect working alternator, and a working tachometer.