My car keeps going dead, purchase a new battery yesterday the brake light and battery light is on will thuis cause car to go dead

YES! You have described a "NO CHARGING SYSTEM VOLTAGE' condition. You should have at least 14 to 14.5 volts at the battery with the engine running. If you don't, there are several possible causes:

1. Blown alternator fuse
2. Electrical cable between alternator & battery is broken or disconnected.
3. Alternator is not working/charging (voltage regulator inside the alternator).
4. Regulator at the alternator is disconnected or an open circuit exists between the alternator's regulator & underhood fuse box.

One quick way to verify "NO CHARGING SYSTEM VOLTAGE" is to start the engine and while it's running, disconnect the NEGATIVE battery cable. The moment you disconnect the cable, the engine will die. If it doesn't, you have a completely different problem -- the battery is dying over-night because there is an electrical drain on the battery after the key is turned off and removed.

If that's the case, and unless you know a good electrician, take it to an authorized Hyundai Service Center and have it properly diagnosed -- best advice I can give you without looking at the vehicle myhself.

You can gain access to Hyundai shop manuals and wiring diagrams by going to www.hmaservice.com and register using the Vehicle's VIN #.

Hope this helps.

IS ALTERNATOR LIGHT ON WITH KEY OUT OF IGNITION IF SO ALTERNATOR IS FAULTY