Author Topic: mirror leds (Read 14527 times)

1LILNDN · « **on:** December 12, 2009, 12:54:47 PM »

OK the other day (tuesday) I put the 921x12 leds in my mirror this morning I was inthe car just before 1st lite and saw the lites don't go completely out. just checked and they stay on very low. Has any body else got this problem??

BLK GXP · « **Reply #1 on:** December 12, 2009, 01:25:47 PM »

this can be a problem with LEDs. They don't use much power, so it might not cause an issue with battery drain. The bcm controls the lights, and on some cars will leak enough juice to illuminate LEDs, but not regular light bulbs. A relay, installed in the circuit can fix this. I had the same problem when I changed my mirror to an Auto dimming mirror.

1LILNDN · « **Reply #2 on:** December 12, 2009, 04:11:36 PM »

This is my stock mirror and I'm waiting on my dimming mirror thanks ,Bobby

2kwk4u · « **Reply #3 on:** December 12, 2009, 07:47:42 PM »

Quote from: BLK GXP on December 12, 2009, 01:25:47 PM

this can be a problem with LEDs. They don't use much power, so it might not cause an issue with battery drain. The bcm controls the lights, and on some cars will leak enough juice to illuminate LEDs, but not regular light bulbs. A relay, installed in the circuit can fix this. I had the same problem when I changed my mirror to an Auto dimming mirror.

I think a small resistor in-line would get you there, too. How are you putting a relay in, BLK GXP? Does it chatter when the BCM tries to dim the lights out?

I have a mirror from an HHR in mine right now, which is an auto-dimming with map lights. The map lights in that mirror ARE LED's, and I'm not having this issue. I might be just lucky, though. I have my wind restrictor LED's wired into the same circuit, though, so they may be resolving the problem by drawing enough current to fully kick out the circuit in the BCM.

1LILNDN · « **Reply #4 on:** December 12, 2009, 09:11:26 PM »

Would it be the type of resistor thathas the line ends ? If so just do a jumper loop between the connector in the back of the Mirror . The first two pins are for the map lites . I

just asking,sort of like getting the dimmer to work ?

2kwk4u · « **Reply #5 on:** December 12, 2009, 11:21:28 PM »

If you jumper it across the pins for the map lights you'll make the problem worse and/or blow a fuse. You would have to put it in-line. I'm not sure what value resistor you would want, but start with maybe a 100 ohm, 1/8 watt. You'll want it in series on the blue/white wire.

I'll caveat all of that with this, though. It's been a good 15 years since I really had to do any work with Ohm's Law math

If BLK GXP has a proven way to solve the problem with a relay, that might be the way to go...

TomatoSoup · « **Reply #6 on:** December 12, 2009, 11:56:34 PM »

My mirror leds go out, but my footwell leds (wired to the same circuit) do not and continue to glow (very) faintly at all times. I actually quite like the effect when driving as it gives a slight "mood" effect inside the car.

I doubt that additional (or lower) resistance will have any effect. I think that it's just a badly designed circuit with an effect that you wouldn't notice with the regular bulbs. May be a contributor to the drained battery syndrome we seem to have - over and above the Onstar drain.

I'd also be interested to see BLK GXP's relay circuit suggestion, as I can't see offhand how you would make this work with the dimmer - at least not without some kind of comparator driver to disengage the relay at low volts (in which case that driver circuit would continue to draw a slight current anyway).

2kwk4u · « **Reply #7 on:** December 13, 2009, 08:35:34 AM »

I defer to your wisdom, Tomato. You lost me at comparator driver.

So do you think switching the mirror lamps to LED's is effectively a faulty BCM test? (not that one could convince a dealership of that, but...) I'd like to compare resting current draw in my car to someone with this issue sometime to see how much more theirs drains the battery at rest. I wonder if GM has a tolerance spec for what's acceptable? 200 mA?

If you're curious, too, I'll test mine, you test yours, and we'll compare results. I'm just talking about putting an ammeter (or in my case, my old Fluke 78 multimeter) in line with the disconnected positive battery terminal to the cable end...

TomatoSoup · « **Reply #8 on:** December 13, 2009, 11:24:53 AM »

Quote from: 2kwk4u on December 13, 2009, 08:35:34 AM

If you're curious, too, I'll test mine, you test yours, and we'll compare results. I'm just talking about putting an ammeter (or in my case, my old Fluke 78 multimeter) in line with the disconnected positive battery terminal to the cable end...

Sure - I'm up for that. Might try to test the draw through the mirror light circuit too, if I can see an easy way to do it without having to remove interior pieces

I doubt though, that this would prove the BCM to be "faulty". It's more likely that this is just the way it is.

2kwk4u · « **Reply #9 on:** December 13, 2009, 12:19:47 PM »

Sorry for the thread semi-hijack, 1 LIL NDN...

Here are my results, Tomato:

It steps up once and down several times before settling...

The initial draw is around 1.3 A

~10 sec mark - drops to 1.2 A

~11 sec mark - jumps to 1.87 A (that's the high point)

~20 sec mark - drops to about 950 mA and stays there less than a second

~25 sec mark - drops to about 570 mA - then to 530 mA

~35 sec mark - drops to 400 mA

~40 sec mark - drops to 370 mA

~55 sec mark - drops to 140 mA and stabilizes

If I pull the #6 fuse in the underhood fuse and relay panel (one of the fuses marked BCM) the current draw drops to just 4 mA. Still, 140 mA isn't bad for radio memory, OnStar, etc.

My car is an '08 GXP with all the electronic gadgets (XM, OnStar, Monsoon, etc). Electronics mods are GMPP (doubtful that has any bearing), rearview mirror from an HHR (with OnStar buttons, and LED's instead of incandescent bulbs for the map lights) and my wind restrictor LED strips, one of which IS tied into the map light/dome light circuit, as I mentioned. I also have my radar detector hard-wired in, but it's on the same ignition-switched circuit that I used to power the auto-dimming and compass functions of the mirror.

I'm not sure how we'll test the mirror light circuit without cutting a wire or removing the terminal from its socket at the BCM connector and probing there, unless it has it's own dedicated fuse. I'll look into that if you want to compare. It's not too difficult to get the terminal free from its socket...

Edit:

I removed fuse 27 in the BCM fuse panel (INTERIOR LIGHTS). My current draw across that fuse is 170-180 mA with the lamps on and 60 mA once they fully power down. At the right voltage, 60 mA of current could keep LED's lit, if I understand correctly. Interestingly enough, there's no difference in the current draw if I unplug my wind restrictor LED strip. I have my +12V source on another circuit, though, and I'm just using the grey wire in the BCM as the ground side. Also, when I was probing with my meter across the fuse terminals, it WAS triggering a BCM relay...

I guess the trunk light is on a different circuit as well, b/c when I opened the trunk it didn't draw any more current across those terminals to turn that lamp on.

1LILNDN · « **Reply #10 on:** December 13, 2009, 01:05:41 PM »

Scott ; so what your saying is at 140ma If I were to start the Car Once a Month theres not enough draw to take the Battery down. then when the dimmer is hooked up it might even go out.

2kwk4u · « **Reply #11 on:** December 13, 2009, 01:43:33 PM »

Well, no. Upon further research, 140 mA is kind of high. I need to try it again and leave it in place for a good while to see if the draw drops again after 10 minutes, 20 minutes...

BLK GXP · « **Reply #12 on:** December 13, 2009, 01:52:16 PM »

What I used to fix my issue is a small solid state relay. Being solid state it does not chatter at all. I tried it first with a standard relay and it did. I ran the LEDs through the contacts of the relay, and trigger it with the wire from the BCM. Keep in mind that the trigger wire from the BCM is the - or ground part of this circuit. I spoke with an "engineer" at Gentex at the time, and he stated that the tolerances from one BCM to the next are wide enough that some cars might experience this issue while others might not. The relay I installed fixed my problem, so I would expect it work on others as well. A resistor might also work, but I have not tried that.

BLK GXP · « **Reply #13 on:** December 13, 2009, 01:54:59 PM »

I read somewhere that the BCM goes into "sleep' mode after 20 minutes or so. I think that's how the battery run down feature works. The draw should drop once that state is reached.

2kwk4u · « **Reply #14 on:** December 13, 2009, 02:12:11 PM »

I'm in the middle of testing it now. After 10 minutes there was no change. That's when I decided to lock the doors and "arm" the alarm. It's still drawing 140 mA, and "spiking" to ~150 when the security LED flashes. I'll give it another 20 and see if it goes into sleep mode.

Edit: OK NOW it's in sleep mode. A whopping 6 mA draw with spikes to ~15 mA each time the security LED flashes.

Tomato, now you have some testing to do

My first round, I did it between the positive cable and battery terminal. Since I didn't really want to stand there holding my test lead on the battery for a half hour, I did this round between the cable feeding the underhood fuse and relay panel and it's terminal (under where the 13mm nut seats). I just clamped one lead to the cable end, and wedged the other lead under the terminal. Clamping to the stud itself is no good, since it's not in contact until the nut is in place (though I guess I could have put the nut back on there, cinched it down, and clamped to the stud...)

2kwk4u · « **Reply #15 on:** December 13, 2009, 02:18:30 PM »

Oh, and NDN, if yours sits idle like mine does at 6 mA, it could sit for months without being started and should have no problem firing back up whenever you need it to.

Tomato, given that your footwell LEDs glow all the time on that same circuit, I'd be curious to know if your BCM ever goes into sleep mode...

TomatoSoup · « **Reply #16 on:** December 13, 2009, 03:16:08 PM »

OK - I started the experiment...

First a caveat... I have a Fluke (brand) autoranging DVM. It only has 10A and 300mA ranges for current, and due to the fact that the current spikes above 1A every time you connect, I have to stay on the 10A range - meaning the lower current measurements may be a tad inaccurate.

Having said that, the measurements so far are a similar match with 2K's (though I've not tracked by the second as he did). I'll leave it for the requisite 20mins and report back.

2kwk4u · « **Reply #17 on:** December 13, 2009, 03:25:46 PM »

Only way I was able to track to the second is b/c I took video of the readout on my meter. Chances are those readings will be inconsequential.

TomatoSoup · « **Reply #18 on:** December 13, 2009, 03:50:21 PM »

Awlrightty then... Full report

Meter connected. door opened and closed (to turn interior lights on), not armed/locked.

0 secs, lights on = 1.58A
~ 20 secs, lights off = 1.45A
~ 1min = 0.13 - 0.14A (i.e. glitching around 135mA)
~ 20 mins = 0.00A

At the 20 min mark, despite the 0 reading, the floor LEDs were still faintly glowing (in my darkened garage), so obviously there was current flowing, but low enough to be obscured by the inaccuracy of my meter at the 10A range.

Interestingly, I disconnected one lead to my DVM and the LEDs took about 5-10secs to completely go out - meaning there's some capacitance in the supply somewhere. Just reconnecting the lead, but doing nothing else, shot the DVM reading back up to a 1.2A value again.

Bottom line, though there's current flow, it's not a whole lot, and apparently not a lot to worry about when leaving the car idle for fairly long periods of time. EDIT: Of course, this may vary if you leave it locked and the alarm energized!

[For reference, my car has Onstar (still inservice) and XM (which I never use and probably lapsed) but not Monsoon.]

2kwk4u · « **Reply #19 on:** December 13, 2009, 03:57:57 PM »

Do you happen to know the forward current rating of your footwell LED's?

The Marshal · « **Reply #20 on:** December 13, 2009, 04:20:38 PM »

What resistance range would be required in a resistor, as a way to stop current in the LED's?

TomatoSoup · « **Reply #21 on:** December 13, 2009, 04:29:38 PM »

Quote from: 2kwk4u on December 13, 2009, 03:57:57 PM

Do you happen to know the forward current rating of your footwell LED's?

Nope. Sorry. I'm using two out of a four-pack of these "Dioder 001.194.24" under-cabinet lights from IKEA. Each has 9 SM LEDs with componentry that allows a native 12V supply and work fine (so far) direct connected to the car supply. Link: http://www.ikea.com/us/en/catalog/products/00119424

TomatoSoup · « **Reply #22 on:** December 13, 2009, 04:36:38 PM »

Quote from: The Marshal on December 13, 2009, 04:20:38 PM

What resistance range would be required in a resistor, as a way to stop current in the LED's?

Because of the way LEDs work, I think added resistance would only make them dimmer, but wouldn't cure the problem. In other words, you'd probably have to add so much resistance that they'd be too dim when fully lit!

In any case, all this shows is that current flows when the lights are supposed to be off. The LEDs are only showing up the problem. The current flow is still there with the original incandescent bulbs, but it's too low to light them at all. LEDs, being so much more efficient, ARE lighting a little with this low constant current.

2kwk4u · « **Reply #23 on:** December 13, 2009, 05:06:41 PM »

Did you check your current draw across fuse 27 in the BCM fuse box, Tomato?

TomatoSoup · « **Reply #24 on:** December 13, 2009, 08:47:39 PM »

Quote from: 2kwk4u on December 13, 2009, 05:06:41 PM

Did you check your current draw across fuse 27 in the BCM fuse box, Tomato?

Sorry, just got back from the movies with the kids (Scrooge).

No, because of how the car's parked in the garage (tight), I can't get to the BCM without pulling it out into the rain, so that check will have to wait a bit - maybe tomorrow.

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Author Topic: mirror leds (Read 14527 times)