absolute hm65 headrest monitor

Hello im new to posting in these forums but not new to the site, my friend recently gave me 2 Absolute HM65 headrest monitors and i tried testing them b4 installing them and i hooled up the red wire to my inline fuse holder that i have on the battery and the ground directly to the negative batter terminal, the unit turns on and it displays the picture but the back light of either two monitors wont turn on. you can hardly see the picture but you can see the things on the screen moving.Idk what it could be i was starting to think that maybe it wasnt getting enough power but i dont know... If anybody knows please help or point me into the right direction. thanks

There is a Fluorescent light bulb behind the display panel.  Either the bulb is bad or the power supply that powers the bulb is bad.  Take the unit apart and there should be a plug with 2 wires that go to the light bulb.  There is a good chance that one wire is pink and the other one white.  Look for burnt components near the plug.  

I opened it just like u told me and i found the pink and white wire, nothing seems to be wrong there but i did notice that there was a little spot where the power cables the red wire, the black wire, and a white wire (which i dont know what it was for) were soldered,is not soldered any more so im going to try to solder it back together and see if that is the problem.

well it wasnt that spot that wasnt soldered i soldered it back and the headrest still didnt work, i continued to disassemble it and saw that it was not the florescent bulb either because it does not look burned. I dont know what to do now? any help ???? :(

Maybe this would help the wires that come out of the headrest are striped meaning they dont have the ends, anyways there is a red wire that i know is for + power, a black one for - ground, a yellow one for the video and a white one i dont connect the white one to anuthing because i dont know what it could be for, i was leaning towards audio but im not maybe this is what is causing the back light to not light up thanks for any future.

Sorry if im getting annoying but by any chance would anybody know what the white wire is for, Im pretty sure that it is the reason why the back light isnt turning on so please anybody with knowledge help, please help

There is no wire that controls the lamp. When the monitor is powered up red and black the bulb comes on. If the white wire is a shielded wire, meaning it has a small center conductor surrounded by a shield wire and the monitor has a speaker in it that wire is for audio. Chances are you will not be using the internal speaker. If it has no speaker it may be a second video input.

Oh well thanks man you have been alot of help when i opened it there was no speakers so chances are that it is a second video input, idk what could be wrong because both the monitors dont light up but i can still see the video. but thanks again i guess they dont work

Well i found out that it is the florescent light that is the problem but what i am not sure is if they arent getting power or if they are just burnt, they dont look burnt so i dont think that that is the problem, again any help is much appreciated thanks