94 ford taurus battery problems

I just recently bought a 94 Ford Taurus sedan from a couple guys. They told me the battery was shot, but besides that everything seemed in perfect condition so i bought it. My brother put a new battery in right (supposedly), but I had the keys on me so he couldnt test it until I got back. 5 hours later, I turn the engine over perfectly, but the cd player and inside lights dont turn on. The dash lights up fine, but as soon as I get moving forward the battery light on the dash turns on (even with a brand new battery). A day before when I was driving the car home with the shot battery (the guys helped me start it with jumper cables), the cd player and lights were running fine. I haven't the slightest idea whats up with it, but I was told maybe the cdplayer wasnt installed right, and that it might be draining the battery? Idk, hopefully someone here can help?

thanks :wink2:

  nightmare3215

yes the cd palyer could be a draw but i don't think it should be enough to drain the battery very quickly. have the altinator output tested and see if it is charging, the prefered output is 14.2 volts and no more than 14.5 which is very high and could overheat/over charge the battery.
ppauley/cobra freek

  ppauley

There are a couple of tests I would do before reaching any conclusions

1. The posters suggestion of checking voltage with engine on to see if alternator is working

2. with key off, lift the cable off of the negative terminal of the battery and hook up a 12 V test light between the neg battery terminal and the cable. If it lights up, you need to investigate and look for a short circuit or a switch which isn't working right (an underhood or trunk light, an improperly wired accessory, etc.)

  tbaxleyjr

take car to advance auto or autozone. they will hitch up charging system to tester. will show if alternator is whacked. that is usually why battery light comes on. sounds like u may have a short some where. most likely suspect is a wire going to cd player. my rule is if someone has messed with something, look there first.

  slipguy

Does it have a real powerful stereo system?

  FordFromHell351

Also, I would check all your fuses, and make sure your stereo (cd player, speakers) are all wired correctly, as well as your headlights. You might need a new alternator or a more powerful one too.

  FordFromHell351

the cd player looks like an amateur put it in.. so i think thats probably the problem. Thanks for the comments, im having a friend look at it wednesday

  nightmare3215