Thomas Minotour battery drain

[Danjo]

Hello all,

I’m having problems with battery drain. I did a little poking around and found LED 5 on fuse block 2 lit up with the bus completely off and closed up. When I open the passenger door, the LED gets brighter. I always thought that LEDs are binary, either on or off, but that’s what I’m seeing. The legend on the fuse cabinet says that LED means the door is open. I found the switch in the manual door opener lever case and unplugged it, but the light is still glowing half-bright.

I know that it’s a pretty rare event that someone else experiences the same short to ground, but who knows? If you’ve had this problem before, please let me know and if you figured out the problem, that would be even better!

Thanks!

Danjo

[peteg59]

Can you pull the fuse that controls the LED?
If so, then check around to find out what isn't working?

Had a Jaguar with a similar parasitic draw that killed my battery in short order and long story short, I was able to pull fuses until the problem was discovered. Turned out to be faulty seat heater.

Good luck on finding your "issue"...

[Cgoggles]

Danjo, did you ever find a source for the battery drain? I have a 2006 Minotaur that is doing the exact same thing.

[CHEESE_WAGON]

Originally Posted by Danjo

Hello all,

I’m having problems with battery drain. I did a little poking around and found LED 5 on fuse block 2 lit up with the bus completely off and closed up. When I open the passenger door, the LED gets brighter. I always thought that LEDs are binary, either on or off, but that’s what I’m seeing. The legend on the fuse cabinet says that LED means the door is open. I found the switch in the manual door opener lever case and unplugged it, but the light is still glowing half-bright.

Danjo

Barring any problem with door switches or sensors, my guess would be something is amiss in the BCM (Body Control Module) or LCM (Lighting Control Module). Most vehicle electrical systems today are controlled by electronic brain boxes that supply and interrupt grounds for electrical circuits based on input from switches such as what you describe.

Some of these switches are normally-closed contacts, meaning the contacts would be closed (completing the circuit) when the door is closed.

i.e., the door being closed completes the ground to the BCM, and the BCM sees the ground as a signal to command the LCM to interrupt the ground to the interior lights.

Others might be normally-open contacts, meaning the contacts would be open (interrupting the circuit) when the door is closed. In this case, the BCM would see the interruption as a signal to command the LCM to kill the lights by interrupting that circuit's ground.

In this case, unplugging the switch would do nothing -- it would simply perpetually tell the BCM to trigger the interior lights through the LCM. You might test all the door switches / sensors to ensure they are okay, then go from there. BCM / LCM issues usually require seeing a dealer.

When it does this, check to see what has power that should not (power windows, stereo, gauges powering up when they shouldn't). That will be a clue as to where the problem is. You could have a relay for Retained Accessory Power getting stuck, which could be an easy fix.

Just my $0.02.

If either of you are near Avoca, NY, you might check out South Main Auto Repair. Eric O is a crackerjack when it comes to electrical issues, but it certainly sounds like a BCM / LCM fault to me.

[Danjo]

Originally Posted by Cgoggles

Danjo, did you ever find a source for the battery drain? I have a 2006 Minotaur that is doing the exact same thing.

I had a bad battery. One was draining the other. If you want some troubleshooting ideas, just reply back.

[Cgoggles]

Thanks! I was suspecting a bad battery, but it was the open door LED that was throwing me off.

[Danjo]

Originally Posted by Cgoggles

Thanks! I was suspecting a bad battery, but it was the open door LED that was throwing me off.

Oh man...that was a journey. At one point I had somehow had the accessory lights switch on. I don’t know how I did that.

So I was doing a parasitic drain test and found that with everything off, doors closed, hood closed, I was drawing about 1.5 amps. When I disconnected the second battery, it dropped to something like 90 milliamps.

[CHEESE_WAGON]

Originally Posted by Danjo

Oh man...that was a journey. At one point I had somehow had the accessory lights switch on. I don’t know how I did that.

So I was doing a parasitic drain test and found that with everything off, doors closed, hood closed, I was drawing about 1.5 amps. When I disconnected the second battery, it dropped to something like 90 milliamps.

That's about what the memory lead for the stereo would pull. I'd say you're okay. I've see where a bad cell could cause a discharge like this, but usually only happens in colder weather (below 40 in my experience).

[Cgoggles]

Thanks for the help, super appreciated!!!!