Thread: D3 Battery Drain - Fuse FL17

That's a fusible link, not a normal fuse. The fusible links normally provide power to standard fuses. Fuse 17 notation is further towards the top of the fuse cover.

FL17 only supplies some fuses in the junction/fuse box.

Edit: If you weren't already aware, there's another fuse box behind the passenger glove box.

Interesting, I never thought about the removable fusible links being sort of in the supply chain to the smaller fuses - that is good to know.

Anyway, a few months ago, I was also having engine starting problems and assumed it may be some electrical draw problem. Ultimately I needed a new starter motor, but in my search for the solution, I started pulling fuses trying to determine normal draw on the battery when the 3 was asleep.

This turned out not be just a simple task of letting the 3 go to sleep and then measuring amp draw on the negative battery post side. (I disconnected the ground cable from the negative battery post and then inserted an amp meter between the end of the ground cable and the negative battery post. I think it is safer that way.)

Initially I found the draw to be two or three amps so I assumed that all must not be asleep or I had a draw problem. I had rolled the driver side window down so as to keep the interior lights off but assumed that since the 3 was not locked, that perhaps that was the problem. Then when I attempted to lock the 3 to immediately put all to sleep, because the bonnet was still up, the vehicle would not lock. As I wanted the bonnet open to get access to the battery, I then manually forced the bonnet alarm sensor switch into the locked closed position and this allowed the vehicle to lock and go to sleep with the bonnet still open.

The amp meter then showed an approximate half amp draw, (0.5 amps), which I regard as normal for most vehicles, the 3 included. That also meant that I did not have a current draw problem somewhere in the 3.

That still left me with figuring out the starting problem, but at least I knew it was not battery draw down related.

I have the Rosen overhead DVD entertainment display and noted with the 3 unlocked, that the Rosen takes its time to shut down, (like about ten minutes), even with the display door closed.

I do not know if that is the way the Rosen is supposed to be that that is how mine seems to operate. The immediate solution is to lock the vehicle and that shuts it down at once. The DVD player was where the big draw was coming from when I did the initial testing. I also noted that even with the 3 unlocked, when the Rosen does finally shut down, (no blue light showing in the DVD slot), that the battery draws drops to about the half amp number so eventually, all was good.

Originally Posted by bbyer

Interesting, I never thought about the removable fusible links being sort of in the supply chain to the smaller fuses - that is good to know.

I should have written that fusible links often provide power to normal fuses. I spotted at least 4 in the wiring diagram that do just that, but some others are just heavy fuses to devices that can draw a lot of current.

Thanks guys, that makes a bit of sense... The search continues! Haha

Its interesting bbyer, that you noticed a 0.5A draw at rest as that's the draw I have sending the batteries flat... I would have thought that half an amp continuous draw would mean that the car couldn't be left standstill for mor than a few days.

Also the fact that the FL17 seems to pick up locking and unlocking, which obviously needs to be operational once the car is left makes me think that the power going to that fuse link is most likely being consumed properly... Also that as you mentioned without the bonet shut and locked it might be drawing more power that it would once it's locked up as the computers might be more active when unlocked.

Food for thought, cheers guys!

Yes, I would agree that even 0.5 amp is still a fair draw over a number of days. I have heard that there is a more dormant state that kicks in after maybe a day or so, but I do not know that for certain.

It seems that for the most part, one can leave the 3 parked for a couple of weeks or so, say at an airport, and it still starts. At the same time, I have heard of guys using the battery from an 18 volt cordless drill to jump start their 3 after a week at an airport - just provided the needed extra power it seems.

If it makes you feel any better, my early 2000 Chev pickup did not last for more than two weeks when parked. About all it had was an engine computer, a door lock remote system and radio/clock keep alive circuits.

My nineties Buick Roadmaster was somewhat better - closer to a month and then dead.

With all this fine detective work, "educated" guesswork and the critiical nature of the hidden current draws I wonder why the forum cannot get a definitive techinical statement from LR as to what really happens.

Many questions surrounding the "mysteries" of the LR electrics seem to arise in this forum. The car has been around many years in its current form - maybe there is a technical paper or well informed LR insider around that can enlighten us all.

Originally Posted by AGRO

With all this fine detective work, "educated" guesswork and the critiical nature of the hidden current draws I wonder why the forum cannot get a definitive techinical statement from LR as to what really happens.

Many questions surrounding the "mysteries" of the LR electrics seem to arise in this forum. The car has been around many years in its current form - maybe there is a technical paper or well informed LR insider around that can enlighten us all.

If only!

Hi Gords and your USI-160 isolator draws about 140ma until in SHEARED mode, till the common battery voltage gets to 12.0v then the USI-160 shuts off and it’s draw is less than 10ma.

Hi bbyer, and your SC80 draws about 240ma till it shuts down then it draws about 5ma.

In both cases, your cranking batteries are left with about 50% of the capacity which is heaps for starting a number of times in the coldest of weather conditions.

With fully charged cranking and auxiliary batteries, your isolators should not turn off unless your vehicles have been left unused for at least 2 weeks. 3 and 4 weeks is common for the isolators to remain on, which means your batteries voltages will not have dropped to 12.0v


NOTE, the power the SC80 and the USI-160 is by design, heaps less than any other isolator and this is why they can be run for so long without discharging your batteries in a few days.

Normal solenoid isolators draw around 700+ma.