I think its a ground issue but I thought I'd run it by you guys just in case. While at a stop light with the turn signal on I noticed that all the lights on the dash would blink in sync. Also the voltage gauge would move back and fourth. It doesn't dip below the line but it does move. Does this with the fogs on and headlights on. Haven't tested yet without headlights. While giving it gas the voltage meter jumps back up and stays steady where it should and all the instruments work fine. So I'm thinking its either the ground, the belt belt I put on, or the alternator itself.
Sounds familiar...lol Yup, I need to do the ground wire thing too. I just started this a month or so ago. Another thing to get to.... ugh...
its not your alt....... check your ground on your battery and then your alt wire.....theres also a few more lying around in your bay you need to check....my first thing would be to unplug your fogs and see if it still happens or not.
most of us here have the jumpy volt meter with turn signals on... You need to purchase a grounding kit.
The '87 did that too. Turn signals on, the cluster lights/voltmeter would dip/flash accordingly. Big 3 upgrade didn't fix it, it kept happening. I had no loss of other lights/voltage (as when the meter was dipping I was still having 14.7v at the alternator & battery). It was just in the cluster itself, I didn't worry about it.