this maybe should be in the stock problems thread, but whatever.

anyway, been having this issue for some time now, but not always... when running the AC anything more than half, maybe 3/4 full fan blast, when I am at idle the voltage drops quickly to 12v, and eventually (fairly shortly actually) starts to drop even more.

my radar detector has some sort of silly "power save" feature that basically complains about low power and shuts the unit off. so when my AC is running full tilt and im at a light, give it about 20-30 seconds and the detector starts "dying" due to "low voltage".

it will stay off for a bit until eventually the car kicks up the RPMs to 1k to compensate for the low voltage of the car (which seems to continually drop, obviously since the RPMs are kicking up). the voltage picks up some, just over 12v or so, but will pretty much drop down slowly again after that "kick" interval.

as soon as i start driving it shoots up to the correct almost 14 volts and im good. I have a volt gauge right there, so i can see all this happening in case you were wondering.

also during this "low power" stage of sitting at a light, the AC does slow down some, probably due to low power available.

sound like the Alternator is slowly taking a dump? battery is new enough (optima red top, yes i know, lets not get into that just yet), about a year old. no other electrical issues with the car; although sometimes the AC does slow down for no reason while driving, then returns to normal after a minute or so.

so what you guys think?

 

I know in my old TA that under drive pulley the alternator did not charge when idling , especially at night , and stereo caused the lights to flicker with the bass. If your not under driving your alternator I'd say it's losing capacity to charge. The blower motor is a high current draw item.

My radar detector has a low voltage display as well in my MINI but only see it when starting the car.

 

i just have a SC reduction pulley, the crank pulley is stock.

i mean, the car does have over 110k miles, so i wouldnt doubt something is starting to give. had my suspicions about the alternator for some time now, just waiting for it to really take a dump before fixing it :P

 

i would imagine the alternator is starting to let go, or the belt is slipping across it

 

Your alternator is weak....the brushes are worn. Very common on higher mile alternators....
If you want to go old school, yank it off, and replace the bearings and brushes.....or just get a new/rebuilt one.....
Internly the s DENSO alternator is a twin to most Toyota/Honda units.....
The failure mode is telling....it is worn brushes....indicates the windings are good...no shorts.

 

HI, Just came out of sushi with son. I started my 02 S and cranked up the AC. It is about 90 degrees outside. The AC dash controls started flashing off and on. The AC compressor did the same. All other systems including radio were fine. I was able to turn off the system eventually by tapping green buttons on left (AC, recirc, etc). All had been fine on the way to dinner. Car ran fine on the way home despite issue.
Does anyone suppose I have an alternator issue too? Alternator is 2 1/2 years old.
Any other ideas?

 

Flashing AC system light indicates an issue with your AC system -- I think it might be in the manual. Sorry -- its late and I don't feel like going outside.

 

Try starting a separate thread......