I have a red light on my mtx audio thunder 895

SOURCE: MTX Thunder problem

Make sure that your connection at the battery is still good-sometimes the wire corrodes up front when your system is installed for a long time-so check that out and of course the fuse that you installed a foot away from the battery so that you dont burn your vehicle down if a short occurs somewhere down the line

SOURCE: mtx thunder 1500 watt amp no sound

Even if there is no visible damage, it could be that one of the transistors is blown, Use a multimeter to check the resistance of the transistors.

SOURCE: Sub not working and red light on amp stays on?

the amp is under to much pressure get a bigger 1

SOURCE: MTX Thunder 81001 wont push subs

first of all you should check the minimal impedance your amp handles , if is class d it should handle between 1-2 ohms total impedance in a mono conection , meaning whatever quantity of subs you have hooked to your amplifier,their total impedance should the minimum the amp handles that way all the power from your amplifier will be used.

SOURCE: i have a mtx thunder 7801 and a sledge hammer box

Sounds like the subs are blown with the voicecoils fused together which means the amp is/was seeing a dead short ( zero Ohms reisitence) not good for any amp. Disconnect the speaker terminals from the amp and see if it turns on. The funny smell might have been the subs blowing up, i'll keep my fingers crossed for you.