I need to get my hands on the electrical diagram for my 04 gxp. I just wanna know what wire I can tap in for 12v constant and griound, although ground should be easy cause I can ground it to the car itself.

Here is a pinout w/ RPO - UZ8 (Monsoon Audio):

Pin [Color] Function

A1 [PPL] Class 2 Serial Data --Primary
A2 [PPL] Class 2 Serial Data --Primary
A3 [PNK] 14 Volt Reference
A4 [RED] FM Composite Signal
A5 [--] Not Used
A6 [PNK] Radio On Signal
A7 [LT BLU/BLK] Cellular Telephone Voice Low Reference
A8 [DK BLU] Cellular Telephone Voice Signal
A9 [BLK/WHT] Audio common
A10 [BRN/WHT] Left Audio Signal (+)
A11 [DK GRN/WHT] Right Audio Signal (+)
A12 [BRN/WHT] Left Rear Low Level Audio Signal (+)
A13 [BRN] Left Rear Low Level Audio Signal (-)
A14 [LT GRN] Right Front Low Level Audio Signal (-)
A15 [LT GRN/BLK] Right Front Low Level Audio Signal (+)
A16 [BLK/WHT] Ground
B1 [ORN] Battery Positive Voltage
B2 [ORN] Battery Positive Voltage
B3 [WHT] Antenna Enable Signal
B4 [YEL] Backlight Lamps Control
B5 [BLK] Ground
B6 [PPL] Amplifier Present Signal
B7-B10 [--] Not Used
B11 [BARE] Ground
B12 [TAN] Left Front Low Level Audio Signal (+)
B13 [DK GRN] Left Front Low Level Audio Signal (-)
B14 [BLK] Right Rear Low Level Audio Signal (-)
B15 [DK BLU] Right Rear Low Level Audio Signal (+)
B16 [BLK/WHT] Ground

so to hook up a constant power I'd be using b1 or b2? I have a volt meter but I just wanna make sure

Correct. These supply power to the head unit, but also switch on/off with Retained Accessory Power control. Can I ask what you're connecting? Depending on what you are trying to add, this may not be your best place to tap power. You'll need to consider the additional current draw on this circuit

I am installing an ipod adapter called the aux-box from pac, I need to get a 12v constant.

Should be okay. Unfortunately, users lose the use of XM or a CD Changer with this. Don't know if it applies to you though.

I don't have a cd changer and xm sucks.. lol. where can I get constant power from tho?

cig lighter?

I read that the cig lighter shuts off after a certain ammount of time. I need constant power.

There is a fuse under the hood which you can move to permit contstant power to the cigarette lighter. Why does this box require constant power, even if the stereo is off? If it'* only an aux input adapter, there shouldn't be any sort of memory settings. I'm not any sort of expert with aftermarket, but ths does peak my curiosity a little. This would only serve as a possible battery killer. The way to change this (I can't remember off the top of my head) is listed in your owner'* manual.