The dome light off the keyless is a switched ground. SO it will have power when the domw light is off. Which means you need to run that wire to one side of the light and then run a constant 12V source to other wire coming off the keyring. This makes it have a power and a ground when the dome light is on. The pinout on the keyless should be on the module itself or you need to use a voltmeter to check it out.
Part number for the keyring is: 84661FC010 comes to $30