After crushing head-on, my Nissan almera 2005 just switched off. The headlamps and water tank for wipers broke. But when I try to turn the key on, the dash body does not light and the positive terminal of battery is hot, what could be the problem or reason

SOURCE: 1993 nissan altima wnt start

Take it to a auto-electric specialist, dont take it to a mechanic.

SOURCE: won't start

There could be a short in or near the ignition switch.

SOURCE: won't start after cleaning battery terminals

Sounds like you have an aftermarket alarm with starter disable. By disconnecting the battery the alarm reset and the defualt setting is usually to set the alarm automatically (active arming). You have three options..
A. If you have the key fob that went with the alarm you can disarm the alarm.
B. If no key fob is available you can disconnect the battery again, turn the ignition key to the on position and reconnect the battery. This usually doesn't allow the alarm to set and allows the car to start.
C. Remove the aftermarket alarm system. This is usually the long term fix i recommend if the fob isn't available. Option B should get you going though.

SOURCE: headlights stay on with key off high beam light on

daytime running light module is defective..it is located around battery tray,near fuse block..needs to be replaced

SOURCE: issue with dash lights dimming while driving,

If the battery and alternator tested fine. I would have the charging system rechecked when engine is hot and at high rpm's. This way the checks are being done as if you were driving and driving for a long time. Alternators can work fine when cold but weaken when hot or stop working. This problem is not rare but only is seen occassionly. Unless it was checked at an electrical shop the average shop doesn't run these tests for they don't see the problem often enough to automaticly run them at all times. Good luck and let me know how you make out.