I already replaced the resistor and checked the relays on engine compartment and also check the fuses on the fuse box.

Well, then the only thing left is selector switch-

I'm assuming this is a manual system, since you said "speed 5", climate controls systems don't use the selector switch and number the speeds.

thanks but I end up replacing the resistor again and i bought it aftermarket this time for $18. bucks and it works again. it has been a week and no problems. thanks again.