Over heating MRV F345 is over heating when being used loud for a few minutes, and the fans arent turning on. Is there a fuse specifically for the fans that might be shot? my MRD M1005 is doing the same thing. both brand new. how do I trouble shoot the problem? I've already redone my ground wiring just in case. running 4 gauge for the MRD M1005, and 8 gauge for the MRV F345

Are you sure it is overheating? Maybe you have the wrong speaker load and it is reacting to that. Is the unit shutting off when it "over heats"? Are you bridging and how many speakers are you using in what configuration (series/parallel)? Since you have two "new" amps doing the same problem and neither fan is turning on then I think you have a hookup problem and not a fan problem. Since you say you are using a large gauge of power wire (I'll assume you have an adequate connection to the chassis/ground) then that leaves only the speaker loading. I think you need to fix this problem quick before it blows your amps though. Good luck.

You trouble shoot the problem by opening unit and force-powering fans to test for overheating during "being used loud for a few minutes". Read the fans' label for proper voltage to apply and proper polarity. I am guessing the fans will run on car battery voltage of 12 volts. Also, attempt to close up the unit to simulate real conditions. There should not be fuses for the fans. If unit is now cooling, then look for faulty thermistor, which turns the fan on during rising temperature. Once thermistor is located, a fast test is to "jumper" its two wires to simulate turn on.