so my batteries died a little bit ago so i replaced them with some bigger ones.the past two weeks my battery light will flicker or come on then off then on and off.but once the light comes on it jumps to 18v.all the times ive seen an alternator going bad the volts drop.anybody have any idea what this means?

 

Check your grounding points for both the batteries, and CHECK THE BATTERY CABLE CONNECTIONS, especially for corrosion and tightness.

First, how many miles are on this alternator? It has stuff inside that simply wears out over time.

The flickering battery light usually indicates the alternator is getting intermittent. Yes, they will do that for a very short time just as the slip rings wear through, or the brushes get to the end of their physical travel. When that happens, the brushes "arc" a bit, which causes the CMOS in the regulator to get "fuzzy", and all kinds of things can get out of regulation.

Seeing eighteen volts means you have maximum current being passed to the field windings, and this is not good in a vehicle that relies so heavily on no more than about 14.5 volts to operate the many computers on-board.

Just as an aside, the small connector that plugs into the alternator has a habit of getting intermittent. Wiggle those two wires a bit (not a LOT!) and see if things change.

I'm just "over the hill" from you if you want to come by. I can take a quick peek at it and see. Also, I will be getting my spare back from a buddy today, which you are welcome to use while you get yours fixed. Takes ten minutes to change. I've just found a VERY good rebuilder in Canoga Park that will not put you through the hassles that a "lifetime guaranteed" one might.

Pop

 

awesome thank you so much.ill try everything you said and go from there and will let you know on that.thanks again