Instrument cluster lights turn off when map light is turned on

[Doubeleive]

I'm sorry, I misspoke....not when I pull down the visors, only when I open the vanity mirror door.

still shouldn't happen, especially if there are not even any bulbs in the visor, opening the lid should do nothing.
that's like flipping on a light switch in your house with no bulb in the light.
if nothing else it's a lead to where the problem is.
which brings up a question? did you remove the bulbs that were in the visor or did you buy it like that? what happens when you put bulbs in the visor?

 

[dkad260]

Call my self reading all of this but have u removed the LED lights and see if it is still a problem?

Today I unplugged the LED fogs and LED low/high beams...no change.

I would unplug both of those visors and see if anything changes

I have unplugged the LH visor and no change, have not done both yet.

still shouldn't happen, especially if there are not even any bulbs in the visor

The pic of the visor light socket was to show where I was probing.

did you remove the bulbs that were in the visor or did you buy it like that?

I only removed the LH bulb in the LH visor to check for voltages.


I put a clamp meter on the battery, with the low beams removed, lights on, door open, HVAC off, I have right about 17A of current draw, if I click the drivers side map light to turn it off, I get 16.3A so 700mA less draw with one map light off...which makes sense. I was looking for a much higher draw to see if anything was shorted.

So I shut the headlights off, key off, and with the door open, I turned off the same map light, same 700mA difference. To be sure the bulb isn't wonky, I pulled it and put it on my PSU to verify the load and at 12.2V it was at 714 mA so that checks out.

Next on the agenda is to unplug both visors and pull the IC to find that junction block. Another possibility is the LED's could have compromised the BCM but if thet did so I would suspect we would have heard of more instances with them? Still doesn't rule out the BCM.

Edit to add: With the lights on, I opened the vanity mirror to the point the IC lights dimmed slightly, I saw right about 100mA less draw when the lights dimmed.

 

[dkad260]

Something to add, if my lights are on in the day, my dimmer knob will dim the lights around the radio/hvac, and pressing the map light button has no effect on the IC lights or lights around the radio....only when the optical sensor senses the dim light and sets the interior lights to their evening dim setting will the map lights dim the IC lights.

 

[mikez71]

Weird, my dimmer doesn't work during the day, only at night.
(when light sensor dims cluster and backlighting).

Daytime I'm full bright, no adjustment..

 

[dkad260]

Weird, my dimmer doesn't work during the day, only at night (when light sensor dims cluster and backlighting).
Daytime I'm full bright, no adjustment..

That makes sense...does it dim the surrounding buttons of the radio? That's what mine is doing during the day with the lights on, but not the nav screen.

 

[mikez71]

Yes, dims all dash lighting, only at night.
But sometimes in the morning it thinks its dark, where dash is dim, and dimmer works.

I don't have Nav..

 

[Doubeleive]

Something to add, if my lights are on in the day, my dimmer knob will dim the lights around the radio/hvac, and pressing the map light button has no effect on the IC lights or lights around the radio....only when the optical sensor senses the dim light and sets the interior lights to their evening dim setting will the map lights dim the IC lights.

ic cluster lights stay on in daytime on these that's normal

 

[mikez71]

Being the BCM controls the dimming, and you've checked the basics, I suspect BCM...
BUT I don't want to be responsible for you spending money and still having problems!

From what I remember, the light sensor has 500ohms resistance in direct sunlight, and 15k ohms in darkness. When you switch from 15k ohms to 500 ohms instantly, the gauge backlight only goes dark for about 3 seconds before lighting up bright, though the rest of the lights brighten instantly. Bright to dim, everything dims without delay..

3k to 5k ohms seems like a hysteresis zone. If near those values, can sometimes take 20 seconds to change brightness.
If bright, going over 5k ohms makes it dim. If dim, dropping under 3k ohms will brighten.
(Maybe a dawn/dusk setting? I swear it's happened to me a few times in the morning, the backlight is dim, BUT gauge only backlighting completely off..)

YMMV

 

[dkad260]

BUT I don't want to be responsible for you spending money and still having problems!

Oh, no worries there, I planned on buying a new OE spare anyway. At least I can test my current BCM and if I do anything to it I have a spare.

I looked back at my LED light order and I don't see any "Anti-Flickering" options with my bulbs but might be an add-on option. I have read of issues with some BCM's and not having the normal load from the OE lights.

 

[dkad260]

Can I reset the BCM with the Tech 2?

 

[mikez71]

I don't remember any option like that... Will update if I find one..

 

[Doubeleive]

Can I reset the BCM with the Tech 2?

reset? not really, the only reset there is to disconnect and reconnect the battery.
if you have a computer with windows 10 you can buy the techline 2 year subscription and a jbox j2534 pass-thru device and have 2 years of programming

 

[mikez71]

.. I have read of issues with some BCM's and not having the normal load from the OE lights.

Good point!

I disabled auto headlights and DRL's, so maybe that has something to do with those rare occasions my gauge backlight is off in the morning, despite other backlighting being on.. and the 3 second delay when going from dim to bright resistances instantly..

 

[dkad260]

I had to edit this post below at the red 'Edit" but wanted to mention here in case anyone has already read through it



I was able to get under the dash and spend some time probing and trying to figure this out.

With both visors removed, there was no change. I have 13.4V at each visor pigtail with the engine running, I plugged both visors back in and I also have 13.4V on each terminal for the visor bulbs with the mirror cover closed...both ends of the bulb socket has 13.4V. If I remove all 4 bulbs, the IC dimming is still an issue and the map light will go out if I press any map light button. When I press the map light, I lose voltage to the visors.




Edit I mistakenly left one bulb in the driver's vanity mirror when seeing 13.4 V on each bulb terminal....was a long day. The bulb obviously doesn't illuminate when the circuit is compromised like this so I thought nothing of it. So now with the bulb removed I now have 12.2 V (engine off now) at only the two POS+ terminals on each visor. I have continuity and .3 ohms from the POS+ bulb tab to the end of the driver's side visor pigtail at the red wire with the mirror tilted down, however I do not have continuity from the 2 ground bulb terminals to the end of the pigtail on the black wire.

The LH visor connector coming from the headliner, I have 12.2V at the orange wire, but I have 1 M ohm to ground at the black wire. I have not checked the RH visor yet with regards to resistance to ground, I will remove that visor again during the day. Now I will pull down the overhead console and look for any broken wires. The fact I have 1 M ohm to ground could be something with the RH visor but I will look into that during the day to verify. The rest of the post is the same. End of edit.






I have battery voltage at both circuits 3040 & 2140.

At the base of the kick panel, I don't know what this is, but it has 4 wires, yellow, grey, orange, & purple. With it disconnected, I have 7.6V on each of the yellow and grey, but when connected, I lose the 7.6 V at both of those wires, the orange and purple I'm not sure but have almost no votage.

I found this connector X9

It is the black connector near the base of the steering wheel in this junction box:

It does have battery voltage but I'm not sure what the 'Interior dimming lamp control", circuit 157 should read. I did not pull any of what looks like 25A breakers.

The only thing I wanted to do today that I didn't was pull down the courtesy light/ map light panel for the front row seats, maybe something is lurking in there.

 

[dkad260]

I wanted to mention that I edited post #54 above in case anyone has already read through it.

you mentioned that the drivers side visor lights are burned out? If so I would try pulling the visor and unclip the wire harness and see if that makes any difference. Then check the resistance on both sides. body & visor.

At the time I did remove both visor connectors, but I did not check resistance to ground from the harness coming from the headliner...not sure why but I think becasue I was trying to finish up before I headed to work and forgot...oops. The 1 M ohms to ground at the harness from the headliner on the LH side now has some merit. I acknowledge the fact it can be frustrating when trying to help someone diagnose a problem and the steps are not carried out and/or also not reported back on, and for that i apologize...I have been on the other end of that before. During the day I will pull down the RH visor again as well as the overhead console and hopefully narrow this issue down.

Thinking more on this, during the last 2 months, on my way home I have been needing to use my LH visor to block the drivers window from the sun, and maybe this possible short could be from the LH visor harness in the headliner but it doesn't look like it would pull on that wire when rotating the visor as there is some slack but anything is possible.

the contact for the switch is at the top center of the flap/cover
there is a plastic nub with metal on the edge, when opened the nub pushes in and makes contact on the switch, which then provides voltage to the lamps.
I have never checked but I would assume the switch is normally open, and grounded (closed circuit) with the flap opened.

I have only checked the LH visor so far on this, but with the LH visor, I did not see any continuity changes with the mirror flap open or closed, but I did see a change on the POS+ circuit when rotating the visor to the down position.

 

[dkad260]

So this saga keeps gaining twists...lol. Adding to the edit above I DO have continuity from the NEG bulb terminals to the end of the pigtail of the visors, but my ohms was reading "OL" with the harness connected to the headliner harness...I was basing it off the reading and not using continuity mode. When I unplug the visor, I get .3 ohms from the NEG bulb terminal to the end of the pigtail, but "OL" when reconnected.

I pulled down the overhead console and also checked the ground resistance from the RH body harness for the RH visor and I have 1 megaohms to ground.

With the headlights off, I have 11.1 V to ground at the RH visor harness, but with the headlights on it drops to 8.9V. At the same time if I check the map bulb in the overhead console I have 11.1 V with the headlights off and 10.8V with the headlights on, much larger drop at the visor.

I disconnected the harness at the overhead console and no change of resistance to ground at the visor harness.

Would that amount of resistance be from a relay?

 

[dkad260]

I'm not well versed in reading schematics, I understand the basics, but I'm getting some time in on this project for sure..lol. All the grounds for the interior map lights and courtesy lights which house my issue, all go through G200 correct?

I checked the RH visor ground wire at the headliner pigtail directly to G200 and had the same 1 M ohms resistance.

What would cause that much resistance in this circuit other than maybe the BCM?

 

[LsHart]

Weird, my dimmer doesn't work during the day, only at night.
(when light sensor dims cluster and backlighting).

Daytime I'm full bright, no adjustment..

Could be on to something maybe? Dash sensor problem?

 

[dkad260]

I put it back together, disconnected the battery for 30 min and restarted everything just to see what happens, still no change.

I'm also wondering again about the rear parking sensor fault....this diagram also includes the dimming feature but will dive into it tomorrow.

Collision Avoidance and Parking Assist Systems — 2012 GMC Yukon Denali AWD V8-6.2L Service Manual | Operation CHARM

Detailed repair manual for the 2012 GMC Yukon Denali AWD V8-6.2L.

charm.li

 

[LsHart]

Man this is really weird. When map light is pushed on, the power is going thru some type of power distribution block and or relay that's killing power to the cluster. Head scratcher!