amplifier in protection mode?

Hey guys, So I am confused as all hell! I just bought a new class D pioneer amp and installed it in my truck. I had a previous amp in it (a MTX 3002) anyways I had been running the mtx for about 3 months with no issues, but I am upgrading my sub so I needed a bigger amp. I unhooked the battery from the car prior to uninstall and install of the new amp. Install everything and hook the sub up and nothing... amp is going into protection mode. Cant figure out for the life of my what is wrong. The amp is sitting on carpet so it is not touching any metal. I get so frustrated with it after trouble shooting everything I can think to do. I unhook the battery again re-install the amp and sub combo I was running before I had any issues and now before I even plug my rca or speaker wires in my MTX is in protection mode wth!?!?!? All good wire back to the battery and no fuses are blown. What the hell is going on here! I have never had this issue before and this is driving me crazy! Thanks Keith

I understand your previous combination worked but have you tried a different ground?Advanced

Have you used a volt meter to verify the amp is getting power and ground?  If you have an AGU type fuse anywhere in the power path to the amp, replace the fuse, even if it does not look blown.

What is an AGU fuse? I have a 100 amp in line fuse about 6 inches behind the battery and then obviously the amp in fused. I will re-check my ground. I took it off and re-sanded all around it and re-grounded it. I tried a 3rd amp and woofer combo and now I am getting occasional power to the woofer but not steady at all. Unlike the 2nd amp the protection does not come on. I am done screwing with it this weekend I will mess with it after work one of these nights. As for my first 2 amps with the protection light coming on is the amp ruined or once my problem is solved will they go back to working? Thanks Keith

Once you get the problem taken care of, your other amps should be fine.  Do you have a volt meter?

My dad does, I will swing by his house on the way home from work tomorrow. What do I need to test as I am new to this. Thanks Keith

Meter set to DC volts, black lead on the ground terminal of the amp, then red terminal on the power connection of the amp.  Notice that reading.  Move the red lead to the remoter terminal of the amp and notice that reading.

The radio must be turned on for both of these tests.

Thank you, I will check it out when I get home today and let you know. Keith

OK so I have 13 volts to the power but only 6.5 to the remote. Is this how it is suppose to or should the remote have 13~ volts to it as well? Also if this is bad how would I go about fixing it? Thanks Keith

The remote wire should be much nearer 12 volts.  I have no idea where you are getting power for the remote wire.  Do you have an aftermarket radio?  If not, where is the other end of the remote wire connected.