So ive been noticing my voltage dropping in manual mode. I had my alternator checked out and it is running fine. So I figured it was the battery so I just changed it yesterday. Bought a brand new bosch agm and had it installed monday. I drove the car this am and it happened again. It has happened with the old and new battery. At first I thought it was my after market stereo. So I decided to drive in Manual with the stereo off.

When I push the car hard in manual I see the volts drop. But when I put the car back in auto grandma mode the voltage rises back up.

ANy Ideas?

Thanks

 

Does the voltage drop in first in manual mode? Does it start to drop in second gear in manual mode?

 

Not necessarily. Today I did two tests. I drove in grandma mode with the stereo playing. Voltage didnt drop until I was driving spiritedly. Then on my way home, I drove in manual mode with the stereo off and the voltage dropped again, while driving fast. I think when the revs get high, thats when the volts drop. But once I drive normal for a minute or two the voltage goes back. Also when I drive like a normal grandma, stereo blasting, voltage will not drop.

Last week the voltage dropped all the way to the last mark and my dash board lights went nuts and stereo went wonky. I had to turn off the stereo and drive real slow

 

Are your battery cables corroded at all?

 

That or it sounds like the voltage regulator is going bad in the alternator.

 

You should try unplugging the rem wire out of your amp/amps so they don't turn on the amp and redo your test. It may be related to where they/you tapped in to get your remote wire signal from.
How long have you had the system in?

V.

 

This is a good possibility.

 

System been in for about 5 years now. Never had this problem until now. Im gonna have the alternator checked again

 

make sure they check it at high rpm since that is when your problem occurs.

 

It could be belt slipping maybe . High demand of dc at high rpm and belt slipping so the alternator cant keep up. And you don't see it in auto mode because you don't push the car let's say beyond 4000rpm.

 

That's true, check the tensioner and belt ribs.

 

Car is almost at 80+K so I just scheduled the 90k service. I looked up the 90k and is says the timing belt changed is recommended so that might be the issue. I let yall know

 

I think you mean serpentine belt and tensioner?

 

OH yea I guess that

 

Got the 90k service done plus belt replaced. Drove car home and went into manual and again the voltage dropped. So far Ive replaced the belt and got a new battery....any other ideas?