I did recently notice a very strange change in the position of the fuel gauge reading when sitting in the car with the key in the first setting, (radio power only) while the laptop is connected to a device, that is connected to the cigarette lighter, that is leaching power from the battery. The gauge seems to climb, and climb and climb. (but only when the key is left in the first position, with only the radio on) If i unplug the device that is connected into the cigarette lighter, the fuel gauge will stop climbing and just sit at the level that is was at when I unplugged the device.

Now, the interesting thing here is, once I turn the key to the second position, (car is not on yet, but power windows, air ventilation works) the fuel gauge will return to the level of fuel that is actually in the tank, weather or not the device is connected into the cigarette lighter. I have been using the "device", I guess I should define that: (allows the laptop to charge using the vehicles battery by means of power conversion), for a few weeks now and have only just recently noticed this strange sequence of events.

I will admit, right before I noticed this start, I got in the habit of turning on the car every 45 min to allow the battery to recharge, (due to the consistent drain because of laptop charging) to make sure the battery doesn't die on me. In doing this, at one point, after letting the battery recharge a bit, I went to turn off the vehicle, but my hand slipped. I am not sure if anyone has done this before, but the car, momentarily shut off, (by force of my hand moving the key out of the third position) but came back on because the key was still in the third position.

That said, I guess, in my case, having the laptop connected to the vehicle is messing with some kind of electronics relating to the gas gauge and the bober inside of the gas tank.. Everything else in the vehicle seems to work properly. It's just a matter of that gauge rising when there is residual drain on the battery when the key is in the first position..

Any help / suggestions on this matter would be greatly appreciated. For the time being, i'll likely just not charge the laptop in the car.

 

Sounds like a power back feed from the laptop batt., does your lighter even work when ign. key is only in the acc. position? 94

 

Yes, the lighter, along with the radio work when the key is in the first position. (I assume that's the 'acc' position) I spoke with my (licensed) mechanic about the issue, and he basically said what you posted FCM. It's (obviously) some kind of electrical 'thing' going on, but is not an issue as is.

I am one of those people that likes to know "why" to just about everything so I'll be having the electrical system tested when the laptop is plugged into the car, in a few weeks time.

Aside from that, however, thanks for the post / info! I wasn't too sure how active this site was, and as I am a newcomer, I haven't posted much. I can post the details on the electrical system test once it is completed.