Monitor install help

[dna59]

I just installed my monitor in my eclipse but i get engine noise in the audio. I've tried everything i could possibly think of and it's still there, what 've noticed is that when i have on everything and i plug out the video cable for the monitor the noise goes away. At first i thought this was because it was next to the power wire which was a mistake i made so i put it on the opposite side of the vehicle and it's still there. The only two things i could think of is that maybe the video plug isn't good quality or maybe the cig. light plug is causing it. would cutting off the cig. plug wire and rewiring it fix the problem or no? I just hooked up a 12volt auxilary source under the dash and plugged the monitor's cig lighter plug in it. Could it be the cig lighter plug isn't grounding it good or something.

[NorCalTacoma]

sorry about the problem but usually it is the quality of the video cable up grade it to something high quality monster etc.