2001 Civic LX Amp and Box install help

You have come to the right place, this is a pretty simple install and it sounds like you have a good idea of how to hook it up. For your remote wire you will want to tap into the radios Yellow/red switched + 12 volt. As far as a signal for the amp you will want to use a good quality high to low converter and tap into both rear speakers as you said. I would suggest you use a PAC SNI-35 http://go2pac.com/products/loc.htm

Below is the wiring diagram for your car

ITEM      |     WIRE COLOR     |POL|       WIRE LOCATION        |

|              12V|white               |+  |ignition harness            ||          STARTER|BLACK/ white         |+  |ignition harness            ||         IGNITION|BLACK / YELLOW        |+  |ignition harness            ||        ACCESSORY|BLACK/ red           |+  |ignition harness            || SECOND ACCESSORY|WHITE/ red           |+  |ignition harness            ||       POWER LOCK|WHITE/ blue          |-  |gray plug above drivers kick||     POWER UNLOCK|WHITE/ green         |-  |gray plug above drivers kick||       LOCK MOTOR|yellow/black        |   |back of the fusebox *3      ||     UNLOCK MOTOR|YELLOW /GREEN        |   |back of the fusebox *3      ||    DISARM DEFEAT|yellow              |   |back of the fusebox *3      || PARKING LIGHTS +|RED / black           |   |back of the fusebox         || PARKING LIGHTS -|blue                |   |factory alarm plug *1       ||       HEADLIGHTS|blue/red            |-  |headlight switch            ||     DOOR TRIGGER|*2                  |-  |factory alarm plug *1       || DOME SUPERVISION|comes on with unlock|   |                            ||  TRUNK/HATCH PIN|red                 |-  |factory alarm plug *1       ||       TACHOMETER|blue                |   |test connector *4           ||      SPEED SENSE|WHITE/ green         |   |PCM *5                      ||       BRAKE WIRE|WHITE/ black         |+  |brake pedal switch          ||     HORN TRIGGER|orange              |-  |steering column             ||           WIPERS|blue (L), blu/yel(H)|-  |steering column             ||  LF WINDOW UP/DN|RED / blk - RED / yel   |A  |drivers window switch       ||  RF WINDOW UP/DN|blu/red - blu/wht   |A  |drivers kick panel          ||  LR WINDOW UP/DN|brn/wht - brown     |A  |drivers kick panel          ||  RR WINDOW UP/DN|blu/org - brn/yel   |A  |drivers kick panel          ||        RADIO 12V|WHITE/ red           |+  |radio                       ||     RADIO GROUND|black               |-  |radio                       ||     RADIO SWITCH|yellow/red          |+  |radio                       || RADIO ILLUMINATE|RED / black           |+  |radio                       ||    POWER ANTENNA|                    |   |                            ||       LF SPEAKER|grn/blk - lt green  |   |radio                       ||       RF SPEAKER|grn/yel - gry/red   |   |radio                       ||       LR SPEAKER|blu/wht - blu/blk   |   |radio                       ||       RR SPEAKER|pink - blu/yel      |   |radio                       |

Notes:

NOTE:  This vehicle has an immobilizer system that needs to be bypassed when adding remote start.    *1 The factory alarm plug is a green plug above the drivers kick panel.  *2 The drivers door trigger is green, front passenger door trigger is lt. GREEN/ red, and the rear door trigger is GREEN / WHITE.  *3 In the top left plug.  *4 It is a 2 pin plug to the passenger side of the battery.  *5 The PCM is behind the glove box. The vss is in a connector A (31 pins), pin 18. The vss is also blue/white at the cruise control module to the left of the steering column.