alt or battery

[Kim K Kaiser]

having just done the ac system,

seems my batter y or alternator may be going out,, 

at off    battery is at about 11.8   while running, doesnt get to about but 12.5 on the meter.  11.8 doesnt seem to give it enought juice to start, so it just cliccks,, i put a battery booster on , fires right up,,

it doesnt get to the 14.9 or so while engine is on.  so, hte question is, is it batter or alternator?

battery is about 2.5 years old, if that matters.

secondly,  would the additionl of the compressor belt to the engine have any effect on the alternator ? would that addition to the spinning have any effects on any other systems.  I havent run the ac but once, since i completed it, and just enought to see if it was cold air,, its only about 45 here for a high right now.

just wondering if there would be any addiitonal drain on the alternator now that ac is hooked up.

[Kim K Kaiser]

you mean with the key on, gen  light on, engine off, the pathway to the light is from alt providing that power to turn on the light, but once the engine is involved, it goes the other way and shuts off the light??

[Jason Edge]

Kim. No. That is not what I said. Just trying to simplify the description of how the GEN light works. With ignition on the ignition circuit sends 12 volts across light and it glows. With alternator charging it sends 12 volts to same circuit from other direction and the two circults cancel each other out with a net voltage of Zero. 

Keep in mind voltage is electrical force. Think of 2 garden hoses with water coming out at 12 psi.  Now connect the 2 garden hoses with a coupler. The pressure cancels each other out and water doesn't run in either direction.

This is really neither hear nor there just trying to give you some idea of how the GEN light works.  
... the main question is did you check that ground wire?

[Kim K Kaiser]

I sure hope so. Tony

[Jason Edge]

I would check the Ground wire at voltage regulator, alternator and make sure connections are tight before just chucking the voltage regulator. These 7 page plus War & Peace essays on relay function and all the suggestions are hard to get thru, but I do not see where Kim checked that ground wire? Perhaps I just missed it.