DIC lights always ON
Thread Starter
Melting Slicks
Joined: Jan 2009
Posts: 3,275
Likes: 739
From: Miami FL
DIC lights always ON
My 2003's HUD controls and DIC buttons back lights won't go off. All other lights are fine and they go off normally after the usual delay (door mounted switches, etc.).
I searched the forum trying to find similar problems and found 2 other people that reported exactly the same problem I'm having, but never came back to tell if/how they fixed it. It looks they are not active in the forum anymore. I tried to contact one of them anyway via email but no luck so far...
For reference, these are the 2 postings I found: Caveboy and philip513. I already re-sat the connector plugs on my gauge cluster and there are no signs of moisture anywhere. I keep a de-humidifier in my garage to keep the humidity level under 55% with very good results.
Thanks in advance for any assistance you can provide me.
************************
UPDATE - RESOLUTION
************************
Although I posted the resolution to this problem back in 2015, I realized it got buried inside this thread when I recently got a PM asking me about this.
I wrote the following summary that I think might be useful for others:
Unfortunately it was the IPC
Here are some links to save me some typing. Basically, these are the options:
I hope this helps.
I searched the forum trying to find similar problems and found 2 other people that reported exactly the same problem I'm having, but never came back to tell if/how they fixed it. It looks they are not active in the forum anymore. I tried to contact one of them anyway via email but no luck so far...
For reference, these are the 2 postings I found: Caveboy and philip513. I already re-sat the connector plugs on my gauge cluster and there are no signs of moisture anywhere. I keep a de-humidifier in my garage to keep the humidity level under 55% with very good results.
Thanks in advance for any assistance you can provide me.
************************
UPDATE - RESOLUTION
************************
Although I posted the resolution to this problem back in 2015, I realized it got buried inside this thread when I recently got a PM asking me about this.
I wrote the following summary that I think might be useful for others:
Unfortunately it was the IPC
Here are some links to save me some typing. Basically, these are the options:
- True solution: replace IPC. Since the mileage is stored in the IPC, you have 2 options to keep the correct reading:
- take/send it to an odometer company to reprogram it
- transfer the EEPROM chip that keeps the mileage from your old IPC to the new one.
- Workaround solution: take the DIC lights off from their broken circuit and connect them to the Parking Lights circuit. This way your buttons will be lit whenever you switch ON your Parking Lights/Fog Lights/Headlights.
- Easier Temporary Workaround: manually control the DIC lights.
I hope this helps.
Last edited by GCG; Jun 9, 2019 at 11:02 AM.
Thread Starter
Melting Slicks
Joined: Jan 2009
Posts: 3,275
Likes: 739
From: Miami FL
I just found another post reporting the same problem I'm having, but he never came back to tell what happened. 
He is not an active forum member, so no luck trying to contact him either.
Just as a reference this is the link.
I've been doing some creative searches trying to find out any info I can on this matter, but I'm running out of ideas
He is not an active forum member, so no luck trying to contact him either.Just as a reference this is the link.
I've been doing some creative searches trying to find out any info I can on this matter, but I'm running out of ideas
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
Well, the obvious thing to start with is to pull your codes and see if anything is revealing itself there. The DIC control is connected to the IPC directly I think so there could be an issue with it and its regulator on the rear of the IPC.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
As far as contacting someone in here, there is the PM which you've already tried and you can send an Email to them via the forum even though it won't show you their email address. Past that, you're out of luck due to privacy rules.
Thread Starter
Melting Slicks
Joined: Jan 2009
Posts: 3,275
Likes: 739
From: Miami FL
So far no luck. I still have the problem
I have tried to contact the 3 people that reported this problem before me, but it seems they are not active in the forum anymore and they never reported back if/how they fixed it.
One of them is a retired engineer (philip513), according to his public forum profile, and when I found him in Facebook my hopes were very high. I tried to contact him via Facebook, but it seems he is not very active there either and I haven't heard from him... You may want to give it a try to see if you have better luck
Please, keep me posted and if you find a solution don't forget to report back here.
I have tried to contact the 3 people that reported this problem before me, but it seems they are not active in the forum anymore and they never reported back if/how they fixed it.
One of them is a retired engineer (philip513), according to his public forum profile, and when I found him in Facebook my hopes were very high. I tried to contact him via Facebook, but it seems he is not very active there either and I haven't heard from him... You may want to give it a try to see if you have better luck
Please, keep me posted and if you find a solution don't forget to report back here.
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Race Director
Joined: Apr 2005
Posts: 11,138
Likes: 11
From: Fremont CA
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18-'19-'20
NCM Sinkhole Donor
Just going to thrown an idea out there because I had a similar situation in another vehicle.
1) Check to see if one of the relays controls this light (sounds like it does).
2) If you can't figure it out, pull each relay one at a time until the lights go off.
3) Once you establish which relay controls it, check for corrosion in the fuse box.
4) Assuming the fuse box looks good, inspect the other relays to see if GM used the same relay in more than one spot. If they did, you can use the other relay to test this circuit. If not, have a buddy come over and borrow his relay for a 20 second test.
This saved me about $200 from the dealer a couple years ago.
Also, remember - you have TWO fuse boxes. One is under the hood and one is on the passenger floorboard behind the carpet.
Report back.
1) Check to see if one of the relays controls this light (sounds like it does).
2) If you can't figure it out, pull each relay one at a time until the lights go off.
3) Once you establish which relay controls it, check for corrosion in the fuse box.
4) Assuming the fuse box looks good, inspect the other relays to see if GM used the same relay in more than one spot. If they did, you can use the other relay to test this circuit. If not, have a buddy come over and borrow his relay for a 20 second test.
This saved me about $200 from the dealer a couple years ago.
Also, remember - you have TWO fuse boxes. One is under the hood and one is on the passenger floorboard behind the carpet.
Report back.
Race Director
Joined: Apr 2005
Posts: 11,138
Likes: 11
From: Fremont CA
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18-'19-'20
NCM Sinkhole Donor
I dug out my shop manual (2004 but I suspect HUD wiring and operation is the same for all year C5's) and looked through the description of operation and the trouble shooting section.
The brightness of the display in controlled 2 ways.
1) the slide switch on the HUD control panel.
2) a photo cell that adjusts brightness based on ambient light conditions.
Wiring schematic does NOT depict a photo cell specifically for the HUD so I suspect the same one that controls the dash and radio back lighting is used for the HUD as well.
The trouble shooting section indicates that the slide switch is replaceable and does describe how to determine if the slide switch is defective. I'll try to scan that section and post it later.
If the photocell is bad then I believe that none of the instrument panel lighting would change intensity either. You can determine that easily enough by seeing if the lighting gets brighter if you cover the photocell. (On the face of the dash on the right side behind a squarish cover with a couple horizontal slots in the cover)
Hope this helps a little anyway.
The brightness of the display in controlled 2 ways.
1) the slide switch on the HUD control panel.
2) a photo cell that adjusts brightness based on ambient light conditions.
Wiring schematic does NOT depict a photo cell specifically for the HUD so I suspect the same one that controls the dash and radio back lighting is used for the HUD as well.
The trouble shooting section indicates that the slide switch is replaceable and does describe how to determine if the slide switch is defective. I'll try to scan that section and post it later.
If the photocell is bad then I believe that none of the instrument panel lighting would change intensity either. You can determine that easily enough by seeing if the lighting gets brighter if you cover the photocell. (On the face of the dash on the right side behind a squarish cover with a couple horizontal slots in the cover)
Hope this helps a little anyway.
Thread Starter
Melting Slicks
Joined: Jan 2009
Posts: 3,275
Likes: 739
From: Miami FL
That's correct. The back lights for the HUD controls and DIC buttons are always on (even after pulling the key and closing the doors).
All other lights are fine and they go off normally after the usual delay (door mounted switches, etc.).
All other lights are fine and they go off normally after the usual delay (door mounted switches, etc.).
Last edited by GCG; Feb 27, 2012 at 05:22 PM. Reason: Adding details.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
Pull your codes and see if anything is showing up. I suspect your BCM is having issues resulting in this. After seeing if there's any codes, I would pull the battery, wait 30 seconds or so and reconnect. Pull and clear any codes following that and see where you stand.
Thread Starter
Melting Slicks
Joined: Jan 2009
Posts: 3,275
Likes: 739
From: Miami FL
It doesn't show any codes. I have tried disconnecting the battery, as you suggest, but nothing... still the same.
I too am inclined to think this is BCM related, perhaps a software glitch/corruption.
I'm under the impression that these specific lights are always fed +12v and it's the BCM the one that controls them providing, or taking away, ground directly to that circuit with no relay involved (it's only a few miniature bulbs consuming just a few milliamps), but I haven't confirmed this. Does anybody have the possibility to verify this?
I too am inclined to think this is BCM related, perhaps a software glitch/corruption.
I'm under the impression that these specific lights are always fed +12v and it's the BCM the one that controls them providing, or taking away, ground directly to that circuit with no relay involved (it's only a few miniature bulbs consuming just a few milliamps), but I haven't confirmed this. Does anybody have the possibility to verify this?
Last edited by GCG; Feb 28, 2012 at 05:32 PM.
Thread Starter
Melting Slicks
Joined: Jan 2009
Posts: 3,275
Likes: 739
From: Miami FL
No, I still have it. I have been trying to avoid going to the dealership, so I have searched everywhere and athough there are cases reporting the same exact problem (please, see my previous posts above), nobody has documented a resolution...
For how long have you been having this problem? Did it appear out of the blue, or after something happened to your car?
For how long have you been having this problem? Did it appear out of the blue, or after something happened to your car?
Instructor
Joined: Feb 2003
Posts: 185
Likes: 0
From: Belews Creek N.C.
I fixed mine, took the light bulbs out, 
I got the car from my dad, I think for 10 plus years it had this issue, his fix was a trickle charger, I tried a new HUD switch, didnt do anything and all lights on it lit up, I removed the bulbs on the hud and dic switches for now the switches are umbilical to the instrument cluster. I think cluster is screwy of the bcm. Its all hit and miss in the dark, the switch was like 100.00 and thats not the issue.
to go out there at night after it been sitting a hour and those switches are lit up is not a good feeling, you know its sucking the battery down and a potential fire issue!!!!!! Now with bulbs taken out at least it wont burn to the ground.
I got the car from my dad, I think for 10 plus years it had this issue, his fix was a trickle charger, I tried a new HUD switch, didnt do anything and all lights on it lit up, I removed the bulbs on the hud and dic switches for now the switches are umbilical to the instrument cluster. I think cluster is screwy of the bcm. Its all hit and miss in the dark, the switch was like 100.00 and thats not the issue.to go out there at night after it been sitting a hour and those switches are lit up is not a good feeling, you know its sucking the battery down and a potential fire issue!!!!!! Now with bulbs taken out at least it wont burn to the ground.
Last edited by lilyorkie; May 21, 2012 at 06:28 PM.
Tech Contributor
Joined: Aug 2008
Posts: 2,902
Likes: 21
From: Oak Hill Virginia
This is pretty strange. Did you ever check for signs of water around the bcm? Do you know anyone with a C5 near you that might be willing to let you swap in their known good bcm to see if you can isolate the issue?
No water around bcm, car was owned by my dad since new in 1999, has 13K miles, sat in garage most life.
Tech Contributor
Joined: Aug 2008
Posts: 2,902
Likes: 21
From: Oak Hill Virginia
EDIT
Forum member Bill Curlee is the resident expert on the electrical gremlins on these cars. Send him a PM with the link to this thread in it; he'll be able to make a better recommendation on where to start troubleshooting this really weird case than I can.
Last edited by cdkcorvette7; May 22, 2012 at 02:01 AM.