Amps died when I connected trailer lights...?

Hey everybody,

Longtime reader/first time poster here...I've been running my sound system (see below for details) with no problems for over 3 years, then everything just went to hell. Here's what happened:

I've been towing a trailer for about a year, and to light up the trailer's brake lights and blinkers, I just spliced a trailer wiring harness into my car's brake lights and rear blinkers. No problems - trailer lights were blinking, stereo was knockin. Recently, I wanted to add lights to the trailer that stayed on at night, so I spliced the yellow wire from the wiring harness into my front headlight. Everything looked great on the trailer, the lights stayed on when I turned on the headlights, but my two amps (1000W Arc Audio and 250W Memphis) weren't turning on. The head unit was fine, but the amps were dead.

I checked my distro block, and the 100 amp fuse was fine. Next, I checked the amps' voltages with my multimeter, and both amps were getting their 14 volts, plus the "turn on" wires were getting their 12. Hm.

The Arc has no internal fuses, but the Memphis has two - I checked those fuses on the Memphis, and sure enough they were blown. At this point, I'm thinking I probably fried the Arc, but the Memphis was saved by it's fuses. With the car off and battery disconnected, I grabbed two more fuses and plugged them in - as soon as I reconnect the battery, the Memphis starts to smoke immediately! Did I fry both my frickin amps?

I've installed a few systems, and I was really into car audio when I put mine together 3 years ago, and I thought I was still up on my electronics, but now I feel like I must have done something particularly stupid. Does anybody know what might be going on?

System details:

2005 Corolla
Kenwood KDC-MP4032 Head Unit
Kenwood Equilizer
RL-p 12" sub
1000 watt Arc Audio amp for the sub
CDT HD Series components up front
250 watt Memphis Audio amp for the comps
Distro Block w/ 100 Amp fuse
0 gauge wiring
Battery Upgrade
No Capacitor
Trailer Wiring Harness spliced into brake lights, blinkers, and recently the driver's side headlight.

Thanks!!