91 ls4 alternator overcharging?
 

I have had the car for about a week now and have fixed a few things, one thing i noticed right away is that every time I started off the blower motor would kick into overdrive, and then slow down when i stopped, i also noted the ABS light would do the same thing.

I didn't think much of it and figured i would look into the ABS eventually.
Well i had a slow day at work on the weekend so i popped in my Clarion DDin DVD player ad sat radio.

All went fine until i went to drive home, as soon as the RPMS came up the radio shut off, scratched my head said screw it and went home(oh by the way i am a seasoned car installer, i was sure the install was right.)

I went back to the shop that night to figure it out. pulled the radio, Ground is good, grabbed my multi meter and BINGO!!.

with the car off voltage sits at 17.2V
18.5 ish at idle and up to almost 19V at about 1500RPM.
Holy Crap!

I swapped my OEM radio back in and all is good.

How on earth are all the computers in the car not fried?
I know they build in tolerances but +5Volts.

I have ordered a new alternator today and will install it tomorrow, i just hope not to have to replace the 6 month old battery to because of it getting overcharged.

Just wondering if anyone had seen this before in these cars.

Thanks

new twist
I talked to the previous owner tonight and the battery and the alternator were replaced 2 months ago>

Now im stumped

I'd pull the alternator anyways and have it checked. Junk in, junk out. The regulator built into the alternator could very well be bad. I don't think it should put out more than about 14.4 volts.

voltage regulator went cuukoo.

thats what i figured i am going to bring it back to the place it was replaced and have it checked, i ordered in a replacement just in case.