Max - First, about the ECU fan. I do not believe that it cools the amp. I've still NEVER SEEN the amp, but the ECU fan is described as "pullling passenger compartment air into itself and blowing it into the ECU/PTCM-RCM-BCM box to cool it". The amp SEEMS to me to be covered up and isolated from any air flow - maybe you DO have a point....

SrW - Well, I am a Kenwoodian, but I was being sarcastic in a way, 'cause I work for the Systems group. We deploy large two way radio systems in heavy industry and public safety. I dont even own any Kenwood audio equipment, even tho I can buy it at 45% off. (Oddly the stuff I work on, I can only get about a 15% discount - explain THAT ONE?!?!?!)

But let's fix the problem... are you saying that you REMOVED THE FACTORY TWEETERS and then INSTALLED AND CONNECTED the aftermarket tweeters, and the problem started? Do I have that right? Or did you disconnect all door speakers, add the Kappas without tweeters (and it worked) and then added the new tweeters (and it failed)?

The reason I ask is that I'm trying to get an exact chain of events that it took to make the amp throw a fit. These amps don't often act up like this.
Also, just to be sure, are you getting sound from all speakers in both doors before it cuts out? I ask this to make sure we don't have a bad wiring problem somewhere, which would be the problem, not the speakers. Again, it seems to take a lot to anger the factory amp.

Let me dig up the into on that Kenwood Head Unit, can you give me the model of it, and the model/specs/what have you on the Kappas and Tweeters? I can usually get the specs on something just from the model number/name.

This should be a resolvable problem without too much trouble...