I do know how to use a DMM! By the way who the hell calls it that any way. Why the hell has this post gotten to this. I have a solder gun and wick and sucker too. I also know where to get diodes if I wanted to replace them (Digikey)!! To up date all you know it alls it is not a diode on the relay board, nor is it a rectifier or the capacitor. I have narrowed it down to the P24 going to the car. I have not yet isolated it from where it changes from P24 to P24C in the car station. I'm going to order a clc board as soon as the customer signs a open order.