Battery drain: Courtesy lights

**Silvestris66** · 02-23-2015, 04:47 PM

We've been having a battery drain problem on my mother's 2003 XC70 for a while, and I think I finally tracked it down by inspecting it at night.

The courtesy lights just above the rearview mirror dim when you turn them off, but they don't turn off completely. They are always on, but at such a low level that I would never have noticed them in the daytime.

One additional detail: My brother went through a phase of replacing every automotive lamp he could with a supposed LED equivalent, and he seems to have done that here. Is it possible that these lamps damaged the control circuit in some way (drawing too much current) or are interacting with it in such a way as to keep them on all the time? The latter seems unlikely to me, but I thought I'd throw it out there.

The lamps turn on and off with the buttons on the headliner, but if they are controlled by a solid-state device, it seems to be leaking current when 'off.'

**kutcht1** · 02-23-2015, 05:29 PM

I would check with a voltmeter. It will tell you for sure.
TomK

**nickbw** · 02-25-2015, 05:26 AM

I recently had an overnight battery drain which left me unable to start the car. It turned out to be due to a short at the driver's side low beam headlight. The harness is fitted with ceramic connectors on an extension cable. The wire had burnt right through! I just fitted new ceramic bulb holders and this time used silicone grease (dielectric) in the hope the problem is sorted!

**cwise73** · 02-25-2015, 08:24 AM

I think that I have heard of this problem with LEDs before. My understanding is that many of the cheaper LEDs will have slight 'glow' when the car is off. My knowledge is a little fuzzy on this since I researched it a long time ago, but I remember the solution being along the lines as using a resistor in parallel with the LED. Or a better solution might be to just replace the lamps and see if it helps.

**billr99** · 02-25-2015, 09:06 AM

Originally Posted by nickbw

I recently had an overnight battery drain which left me unable to start the car. It turned out to be due to a short at the driver's side low beam headlight. The harness is fitted with ceramic connectors on an extension cable. The wire had burnt right through! I just fitted new ceramic bulb holders and this time used silicone grease (dielectric) in the hope the problem is sorted!

If you have the original leads, the combination of DRL, bulb heat, recyclable plastic and an enclosed space breaks down the plastic bits of the connector after about 8-10 years. First car I've had that has shown the problem, but not all that surprising if you consider the relatively recent (as in last 15 years or so) requirement to make all this plastic able to be recycled. I replaced mine with ceramic connectors about 5 years ago and haven't had a problems or indications of degradation since. In any case, it is not inconceivable that as the plastic part of the connector breaks down that it would not be possible for a slight short to be created. One that would be sufficient to bleed power but not bad enough to pop a fuse. Not unlike the more common (at least for me) problem of the slightly shorted glove box light. I've had that happen on a number of cars over the years and it is always a tough one to track down.

Cheers,

Bill

**cwise73** · 02-25-2015, 09:23 AM

Here is the thread that help me pick LED lights for my XC. They have a section that mention glowing LEDs, but say that it will not drain battery

http://forums.swedespeed.com/showthr...read-(S60-V70)

LED has dim glow when off

This is an issue with the P2, it will not drain the battery since the lights go out after the main relay disengages

Fix is to install a resistor in parallel with the bulb, see http://forums.swedespeed.com/showthr...all-and-Photos

Even though it says it will not drain the battery I would replace the LEDs anyway. Go back to the original bulbs, or replace them with newer LEDs. I got a complete V70 set from a Sweedspeed member and it only set me back about $40, and I have no glow with those.
How old is the battery in the car? If it is the original, it might be time to replace.

**Silvestris66** · 02-25-2015, 09:58 AM

We've already tried battery replacement.

Also, I was fooled by the fact that the courtesy lights stay on for ~10 minutes after the door has been opened. They eventually went out, so I guess I'm going to have to monitor current draw while pulling fuses. It's definitely a slow drain. It only drains the battery such that the car won't start if left sitting for over a week.

I'm getting nostalgic for the old days when car electronics turned on and off with a switch--and that was it--but those days are long gone at this point.