First, you won't be able to measure an 80hz 90% PWM signal with a normal DMM, maybe a high end fluke with trueRMS but anything under $400 won't show the correct value. Most of the time, the signal is at full system voltage, with short intervals of 0v (that's what PWM is), inexpensive DMM will average 8 or so consecutive ADC readings which will be very close to full battery voltage.So I decided to do some testing of my own ... my DRL are still in operation knowing that the CEM PWM the voltage to be a constant 13v at the bulb I figured my voltmeter would also see 13v and I could see if the CEM also PWM the voltage when the switch is in the "Manual" On postion (last position on switch). I found something rather odd I was getting full system voltage at the lights in both DRL and Manual on position does that seem odd to anyone else?
Second, was the engine running? When the engine is off, the PWM is disabled (presumably, as the input voltage would be lower). This is actually how I figured out what was going on, the BOW3 would work with the engine off but not while it was running - the opposite of what would happen if there was no regulation.