Ok I have some problems with my voltage on my 01 marquis. I tried to install a second battery had my buddy helping me he drove the screw for the waffle holder into body and into frame. And plugged battery up before I checked everything and then there was smoke. I went through everything I know of and found my ebrake cable cooked to frame. I removed everything wires battery ect.. and i still have voltage drop. I took to shop they said they went through all grounds and found nothing wrong but alt acting funny so I replaced alt and battery. Now the drop isn't as much when I hit brakes but it does drop alot sometimes. I have no clue what I could have done or where to look next if you guys can help I would appeciate it. If not I taking back to shop tues. or weds. and will have to put off exhaust again.thx

 

Did the screws hit a wiring harness?

 

That is really strange, I would def take it back to the shop and see what they think.

 

no didnt hit harness. i have not a clue cause i never paid much attention to gauge before. i had a couple amps hooked up and no dimming of lights before. i have voltage drop everytime i hit the brakes tho or turn on anything. especially after i drive around town for awhile. i also cant find a E.V.T.M for my car can anybody help. also you guys think it could be my 0-gauge wires for the big 3 upgrade

 

Where did you install this second battery? Sounds like you might have it in the trunk, & if so I would suspect a voltage drop with the long battery cable. Are you grounding it thru the frame or with a second cable up to the the first battery grounding point? The frame &/or body grounding points might have high resistance between the back & front of the car.

You might need a 00 cable for that distance.

 

i did have it in the trunk. i have removed all the wiring and 2nd battery. just had the big 3 upgraded. i removed all the 0-gauge wir tonight and but stock wires on and still the same. i just dont get it. i have power to everything and it all works fine. i calling dealership in morning to set up time to drop off. unless you guys have any other ideas to try. i love my car have wanted one forever so i dont want her limping arond lol. i not rich so lets hope i dont get raped at the dealership. cross your fingers