Circuit breaker 401 remaining warm while looking for parasitic drain.

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Ixlr8nAk

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Recently noticed our battery voltage dropping from 12.8 to 12.37, 12.44 over night.
Thinking our Alternator may have had a failed diode, due to a registered amp clamp reading while engine off, And a seeming drop out of amperage at low engine RPMs.
So the vehicle now has a new alternator, and the perceived amp drop ( lights dimming, heater blower speed change ) no longer happens. But the overnight drain continues.
Employed a IR camera to start tracing active circuits. Opened the passenger door, and latched the latch, and waited for modules and such to shut down. Then examined the fuse box for activity.
The only stand out was circuit breaker 401. Wiring diagram shows Relay 2 as providing power for CB 401, so I took out the relay and bench tested it. It checked out fine, but the wiring diagram I have, does not show where non energized power goes, only that when energized it goes to CB 401.
Checking CB 401 after having relay 2 out for 40 minutes, and before reinstalling it, circuit breaker 401 had remained warm ( aprox 54 degrees, and its 34 outside ) indicating activity.
Window controls and sun/moon roof are all on this circuit, but even with the sun roof module on the circuit, I do not see another power feed to other components. Wondering what else could be powering 401 if the relay 2 is not activated.
The passenger side window switch had stopped working long before noticing the parasitic drain. Upon disassembly I found contact burning on its mechanism so as I had done before, cleaned them and the points on rocker plates. Checked CB 401 while it was out, and it was still active. Might have nothing to do with the drain, but it still does not operate the window.

Any Ideas why CB 401 might remain active? Relay 2 did not click when being reinstalled, but all windows do operate from drivers door main switch and moon roof operates as well.
 

whtbronco

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I keep reading and thinking about this. So far I can't get a good feel for what's wrong.

What a terrific idea to use IR to identify what has power. I never would have considered that, but if there is power there is gonna be some heat.

I'm not sure this diagram will help, probably what you are looking at:
1768698823484.png
 

Vincent Vega

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@whtbronco Thanks, this is interesting. Does this diagram indicate that the parasitic can be narrowed down to either the window switch or the roof opening, or am I being too simplistic (as usual)? It might be possible that if the Accessory Delay is providing constant power when it should be, 401 could increase in temperature, but I am not sure.
 

whtbronco

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@Vincent Vega Well it seems reasonable that the draw is related since Ixlr8nAk identified CB401 as getting power. I just figured the diagram might help. I'm certainly not sure what the cause of the parasitic draw was or is.

 

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