I have a general question about amps with cooling fans. I understand the answer may not be the same for all amps. Do they draw cool air into the amp or push hot air out? Simply, if the amp fan turns on and I were to place a feather next to it will it be pushed away or sucked in? It might seem like a stupid question but in order to get the most out of a fan it has to be mounted in the right place in relation to the amp. I’m working on installing a Kenwood XR-5S (5-channel, 80W x 4 + 350W x 1) on the back wall of my 2006 SCREW. My truck has the audiophile system with the sub so mounting it under the rear seat isn’t an option. I’m considering mounting a fan back there as extra insurance against overheating. The fan will be controlled by a lighted toggle switch I already have in the dash. I’m going to wire it to the ignition so it will only work when the ignition is on. I want to be able to turn it on when it’s hot outside and/or when I’m pushing the amp. As everyone who’s installed amps back there knows it isn’t very accessible and I don’t want to have to pull the seat out to trouble shoot an amp the shuts off when it’s hot.

 

A fan would be a great choice with a kenwood amp, they got hot, fast. In your case you should want air blowing across it to help cool it down since it will be an external fan. Try to keep the fan at least about 5" away from it so it has room to spread across it the amp case. Generally if it was an internal fan, it would follow the way a computer/laptop would where it would pull the hot air out.

Also instead of toggle switching it, another idea would be to run a relay using the power and ground from the amp (it's a very low current draw for a fan so it won't make a noticeable difference) and tapping off the remote wire for it to signal the relay to switch it on. So basically it would cut on and off with the amp.

 

You could use a close on rise "snap disc" thermostat attached to the heat sink of the amp.