Originally Posted by Drifter420
Does anyone know how much ohms or resistance the LCM has to see before it thinks the light is blown? Or does it just have to have continuaty (sp?).
From what I read of it in the FSM, I think of it as monitoring current flow on each lighting circuit (or _branch_ of the lighting circuit; although one fuse protects the running lights in general, the Adaptive Lamp Monitor module monitors different branches of it with different bulb groups in each). It compares what it'* measuring now (in amps, I guess) with what it measured during the last driving session, or maybe an average of some number of previous sessions, and if it doesn't see as much flow as it did last time, it flags a warning that a bulb is out.
So I don't think it would (or could) be measuring resistance -- for one thing, it doesn't warn of a blown bulb unless or until that circuit activates. Even though the power is coming from upstream of the ALM; the path from the ALM to ground through the bulbs is always there, so if it was measuring resistance, it wouldn't need to wait for you to turn on the lights before telling you that a bulb was out.
As for continuity, that will always be present as long as at least one bulb in the circuit is good, and yet the ALM can successfully monitor circuits having upwards of ten bulbs all in parallel, so I would say it'* measuring current flow, and comparing it to a stored history for each circuit.