1998 Dodge Ram OE Wiring Harnesses & Stereo Adapters Dodge Ram 1998, Factory Replacement Wiring Harness by Scosche®, with OEM Radio Plug and Provides 4 Speaker Connectors. Up yourself and your tunes over the factory installation with top-of-the-line audio products from Scosche. 1998 Dodge Ram 2500 Truck | Stereo Wiring Diagram 1998 Dodge Ram 2500 Truck Stereo Wiring Information. Radio Battery Constant 12v+ Wire: Red Radio Accessory Switched 12v+ Wire: Red/White Radio Ground Wire: Chassis Stereo Dimmer Wire: Orange/White Stereo Antenna Trigger Wire: Yellow Left Front Speaker Positive Wire (+): Dark Green Left Front Speaker Negative Wire (-): Brown/Red Right Front Speaker Positive Wire (+): Violet 98-01 audio wire colours (head unit) | DODGE RAM FORUM Car Radio Constant 12v+ Wire: In my 1998 RAM 1500, the 6 pin speaker connector in the doors are wired as follows: We’re the ultimate Dodge RAM forum to talk about the RAM 1500, 2500 and 3500 including the Cummins powered models. Full Forum Listing. Explore Our Forums.