My 99 s70 t5 suddenly began to act up. I have a couple amps in car and factory electrical. I have upgraded ground side of electrical but I havnt done the positive side at alternator yet mainly cause I can barely see alternator..

but here is the scenario..

about 1 month ago when I was really jamming the stereo totally shut off for a second , two at most..came right back on but still had all memory so it was still getting some juice. only did it once. I had got after car right after to do some work at house..that was where it happened..as I pulled up.

fast forward to yesterday/today....

I changed out the amps I had for 2 other amps over the weekend and they were rated roughly the same output and should have drawn about the same amperage from system.

suddenly lately when playing system loud it is cutting off. the radio shuts off and on but mainly when volume is up but not 100% it has done this at low volume too.

I would normally think bad connection but I redid all of that yesterday to elimate that. I mean to say I redid it at the deck so no loose radio connections ..

so playing it some more i notice that when I have heat going on full with temp selected I have no issue but if the stereo is on and I switch the heat to "auto" then the car cuts out for a second like the power is out but only for a second. I did this multiple times same result. cuts out for 1 sec and then fine.

if stereo is off and I do the same thing above I get no cut out. the car does not cut off. it just goes from manual to auto no issue.

this is leading me to believe the amps are pulling just enough to cause shortage in power. if this is possible. I have had hundreds of amps and never run into a problem. I would say it was the new amps but it did happen with the old ones too.

I am wondering if battery is going to crap or if its the alternator and how can I tell? battery is easy to test..I dont know how to test alternator and before I go to stupid parts house and have some teen tell me I want to know what you guys think.

also when the car stutters when switching from manual to auto on the heat the ABS light and the Brake light both stayed on last time. then they went off.

another reason I think its the battery or alternator. I had thought it was my radio until the car started to act funny.

advise on alternators also appreciated. I am sure its no fun to change so I dont want to do it more than once.

 

How old is the alternator?

 

dont know. had the car about 1.5yrs

all the electrical issues have stopped since I unhooked my sub amp.

anyone know the amerage of stock t5 alternator?

 

I believe it's 100 amps. There should be a tag on it with the rating.

A lot of amps pull the power reguardless of volume setting. Most people install a spare battery when doing power audio system set-ups.