Flip Down Video in 98 Sienna problem with wiring

I have installed a flip down monitor and dvd in my 98 Toyota Sienna minivan.  Everything is working great EXCEPT...the dome light fuse keeps blowing.  I don't really need the light in the flip down unit, but I'd like to do the job properly.  The Flip Down Dome light has three wires (black, red and green).  I am using a tap to connect directly into the the two power lines going into the existing dome light.  I am grounding the black to the frame (which is the only way that see the existing dome light is getting a ground).

I am new to this, but I must be missing something.  Is there anything special about how cars handle positive and negative connections?

Thanks

My suggestion would be go ground to a different spot ( clean of paint and also ant debris ) and also the Toyota has a ( - ) dome light and door trigger system. 12 volts at rest and ( - ) when dome light is activated. Make sure that the RED wire that the overhead unit is in fact receiving a 12 volt signal and not a ground signal. BTW: Where did you hook up the RED and GREEN wires to ??

The red wire (from the Flip Down light) is hooked into the Toyota RED / Black wire.  The Green wire is hooked into the toyota RED / White wire.

I am reading in other forums about a "negative trigger" wire for the courtesy/dome light.  Could this be my problem, and if so, what is the proper way to wire it.

Thanks

What does the instructions say about what polarity trigger each wire needs ? The RED wire is a 12 volt constant wire ( check to be sure of this with the instructions ) and the GREEN is the activation wire from the domelight or door.

According to the instructions:

Red - Power Supply (12V)

Green - Interior Light System

Black - Ground

Thanks,

double check your instructions, a lot of units require you reverse the 12v and ground wires when the car has a negative trigger system. By the way I always use all three wires at the factory harness. This will insorporate the fade out and time out features of the factory lighting system.

cp

The RED / white is the dome trigger and the RED / black is the dome supervisor.  What is the difference?

Thanks

RED / White is the door trigger and the RED / BLACK is the option on vehicles that allows the dome light to operate after the last door is closed or the first door is open.

So I should connect the green wire to the dome trigger (RED / white), the red wire directly to the wiring harness and black ground to the frame.

Thanks,