I just had an after market stereo system installed on my 2003 Dodge Ram turbo diesel Cummins. Ever since then the battery guage, fuel gauge, and the speedometer doesn't work. Also the parking brake light stays on even though it's not engage. The abs and engine light is also on. Someone suggested that it might be the ecm. I'm trying to find a wiring diagram to find out if the instrument cluster wires are connected to the ecm. Need some help here.