Q7 Tail light configuration question
05-16-2016, 06:18 PM
#21
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Tailgate Indication and Rear Light Cluster
Hi all,
I know this is an old thread, so I understand if there is no other info available on this issue. I just wanted to get a little clarification on how the tailgate system works on a Q7 before I order any parts.
First, I have to say it's been a long time since I've visited this forum when I owned my 2000 A8. I recently got myself back into a pre-owned 2008 Q7 Premium 3.6. I really love this vehicle!
I'm having intermittent issues with the tailgate open indicator coming on in the dash. Originally I had no idea it affected the rear cluster lights until I installed the facelift LED tail lights. It was then I noticed that the lights in the bumper would take over and my new LED tail lights were not being utilized. I read through the threads including this one and wanted to see if I could get more details on how the system works. So here is what I have tried.
I disassembled the latch mechanism where the two microswitches are near the storage compartment above the spare tire. I removed the sensor. The actuator felt a little "Hitchy" so I assumed that was the issue. Just to be sure, I took out my multimeter to test the switches. That is where the confusion began. I measured at both sensors, one sensor measured around 6.5V actuated (closed), and 0V deactuated (open). But, the other switch read opposite (0V actuated (closed), and 6.5V deactuated (open)). My first question is, is this normal operation or are both sensors supposed to read the same?
Next, I took readings at the connector and read the same as I did at the sensor. I thought to read the signals elsewhere, but I see that after the connector, the wires run directly into a harness bundle that runs off to the right side of the car.
My next thought was that the tailgate was not closing in far enough to fully push the flaps in on the assembly. Hence my next question...specifically which part of the tailgate latch actually makes contact with the flaps to disengage the switches?
With the car running and the hatch open, I stuck my fingers in and physically pressed in the flaps to manually deactuate the switches, but the liftgate open indicator on the dash did not go out. Could that be because the switches are not the only system that monitors when the tailgate is open?
Since I am getting signals at both switches and at the connector, is there possibly an issue with the convenience module that receives these signals? I remember reading something about a recall for a firmware update for the module due to the struts weakening.
I will go ahead and order the switch assembly, but I'm worried that since I am reading signals from them now, will it be in vain and find there is separate issue.
Any additional info would be greatly appreciated.
Thanks,
I know this is an old thread, so I understand if there is no other info available on this issue. I just wanted to get a little clarification on how the tailgate system works on a Q7 before I order any parts.
First, I have to say it's been a long time since I've visited this forum when I owned my 2000 A8. I recently got myself back into a pre-owned 2008 Q7 Premium 3.6. I really love this vehicle!
I'm having intermittent issues with the tailgate open indicator coming on in the dash. Originally I had no idea it affected the rear cluster lights until I installed the facelift LED tail lights. It was then I noticed that the lights in the bumper would take over and my new LED tail lights were not being utilized. I read through the threads including this one and wanted to see if I could get more details on how the system works. So here is what I have tried.
I disassembled the latch mechanism where the two microswitches are near the storage compartment above the spare tire. I removed the sensor. The actuator felt a little "Hitchy" so I assumed that was the issue. Just to be sure, I took out my multimeter to test the switches. That is where the confusion began. I measured at both sensors, one sensor measured around 6.5V actuated (closed), and 0V deactuated (open). But, the other switch read opposite (0V actuated (closed), and 6.5V deactuated (open)). My first question is, is this normal operation or are both sensors supposed to read the same?
Next, I took readings at the connector and read the same as I did at the sensor. I thought to read the signals elsewhere, but I see that after the connector, the wires run directly into a harness bundle that runs off to the right side of the car.
My next thought was that the tailgate was not closing in far enough to fully push the flaps in on the assembly. Hence my next question...specifically which part of the tailgate latch actually makes contact with the flaps to disengage the switches?
With the car running and the hatch open, I stuck my fingers in and physically pressed in the flaps to manually deactuate the switches, but the liftgate open indicator on the dash did not go out. Could that be because the switches are not the only system that monitors when the tailgate is open?
Since I am getting signals at both switches and at the connector, is there possibly an issue with the convenience module that receives these signals? I remember reading something about a recall for a firmware update for the module due to the struts weakening.
I will go ahead and order the switch assembly, but I'm worried that since I am reading signals from them now, will it be in vain and find there is separate issue.
Any additional info would be greatly appreciated.
Thanks,
Just to build on knowledge base: There will be fault codes 02914 and 02915 as well as 2 lamp codes.
Emergency function
In the event of a fault in switches G525 and G526,
the system switches over from the main rear lights
in the tailgate to the additional rear lights in the
bumper. This action is not indicated in the dash
panel insert.
In this case, a new attempt to switch on the main
rear lights in the tailgate is not made until the next
ignition OFF/ON cycle.
So, no dash warning.
These sensors are actually micro-switches G525 (red,left) and G526 (red, right). There is actually a flap (yellow) that operates the open or closed position of the two micro-switches.
The micro-switches feed the CAN-BUS convenience system central control unit 2 J773 which directs the operations. Am hoping to dig into it soon.
Emergency function
In the event of a fault in switches G525 and G526,
the system switches over from the main rear lights
in the tailgate to the additional rear lights in the
bumper. This action is not indicated in the dash
panel insert.
In this case, a new attempt to switch on the main
rear lights in the tailgate is not made until the next
ignition OFF/ON cycle.
So, no dash warning.
These sensors are actually micro-switches G525 (red,left) and G526 (red, right). There is actually a flap (yellow) that operates the open or closed position of the two micro-switches.
The micro-switches feed the CAN-BUS convenience system central control unit 2 J773 which directs the operations. Am hoping to dig into it soon.
05-17-2016, 04:40 AM
#22
AudiWorld Super User
Was it all working correctly before fitting the LED rear lights?
If you are getting the tailgate open warning it sounds like it is the switches or the wiring at fault.
If the bulb monitoring detects a failure of the lights in the tailgate it can also switch over to the rear bumper lights even if the tailgate is closed. In this instance you should see a lamp failure on the dash.
If you are getting the tailgate open warning it sounds like it is the switches or the wiring at fault.
If the bulb monitoring detects a failure of the lights in the tailgate it can also switch over to the rear bumper lights even if the tailgate is closed. In this instance you should see a lamp failure on the dash.
05-19-2016, 05:29 AM
#23
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Was it all working correctly before fitting the LED rear lights?
If you are getting the tailgate open warning it sounds like it is the switches or the wiring at fault.
If the bulb monitoring detects a failure of the lights in the tailgate it can also switch over to the rear bumper lights even if the tailgate is closed. In this instance you should see a lamp failure on the dash.
If you are getting the tailgate open warning it sounds like it is the switches or the wiring at fault.
If the bulb monitoring detects a failure of the lights in the tailgate it can also switch over to the rear bumper lights even if the tailgate is closed. In this instance you should see a lamp failure on the dash.
The open hatch indicator was always intermittent, sometimes it would come on, sometimes it wouldn't. I just wanted to make sure there wasn't another issue before I went ahead and ordered the new assembly.
Thanks for the input.
05-30-2016, 05:43 AM
#24
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As I suspected...same problem after replacing part
Was it all working correctly before fitting the LED rear lights?
If you are getting the tailgate open warning it sounds like it is the switches or the wiring at fault.
If the bulb monitoring detects a failure of the lights in the tailgate it can also switch over to the rear bumper lights even if the tailgate is closed. In this instance you should see a lamp failure on the dash.
If you are getting the tailgate open warning it sounds like it is the switches or the wiring at fault.
If the bulb monitoring detects a failure of the lights in the tailgate it can also switch over to the rear bumper lights even if the tailgate is closed. In this instance you should see a lamp failure on the dash.
So today I received the new microswitch assembly from ECS Tuning. I installed the new part, and to my dismay, just as I suspected the problem still persisted. As I did before installing the new part, I re-checked the signals with my digital multimeter at the switches, and at both sides of the connector and got the same readings as I did on the original part. The open latch indicator is displayed on the dash when the hatch is closed (see attached). The signal indicator lights in the hatch are operational at that time. But after coming back from a drive, before turning off the car, I'll put the car in park and check the lights again, and sure enough the bumper lights have taken over.
My question is, is there another place that I can check those signals from both switches, maybe at one of the comfort modules? Is it possible that the comfort module is malfunctioning? Additional info:
I'm not sure if this has anything to do with the taillight configuration issue, but I'm also having an intermittent issue with the side assist feature. The feature will work for several weeks, then suddenly stop working, and display "Audi Side Assist Malfunction". When the malfunction occurs, it will not work for a week or so. Repeatedly pressing the button will eventually force it to start working again, and when it does, it usually lasts a week or so, then returns to malfunctioning again.
05-31-2016, 06:09 AM
#25
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This has happened with my new Q7 also. My service manager tells me there is a technical bulletin out about aligning the switch with the hatch lock, and that one of his techs can do it in a very few minutes. So, when the 5000 mile service comes, I'll have it repaired.
BUT, my fix is two pieces of double-sided tape, like 3M makes, cut to fit on the front surface of the latch body and increase the thickness by about 1-2 mm. And that fixed it for now!
Hope this helps someone else!
BUT, my fix is two pieces of double-sided tape, like 3M makes, cut to fit on the front surface of the latch body and increase the thickness by about 1-2 mm. And that fixed it for now!
Hope this helps someone else!
06-23-2016, 07:53 PM
#26
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Was it all working correctly before fitting the LED rear lights?
If you are getting the tailgate open warning it sounds like it is the switches or the wiring at fault.
If the bulb monitoring detects a failure of the lights in the tailgate it can also switch over to the rear bumper lights even if the tailgate is closed. In this instance you should see a lamp failure on the dash.
If you are getting the tailgate open warning it sounds like it is the switches or the wiring at fault.
If the bulb monitoring detects a failure of the lights in the tailgate it can also switch over to the rear bumper lights even if the tailgate is closed. In this instance you should see a lamp failure on the dash.
I also noticed something that I'm not sure is related of not, but my side assist also works intermittently as well. When it works, it works, but sometimes I get the "Audi side assist error" warning. I never noticed it before, but it seems as if the side assist stops working whenever the open hatch indicator comes on in the dash display. The other day the open hatch indicator did not come on and I had a thought to try and engage the side assist, and low and behold, it worked! Eventually the open hatch indicator came on again, and sure enough the side assist went out again. Is it possible these issues are related? Are they controlled by the same module?
06-24-2016, 05:12 AM
#27
AudiWorld Super User
Not the same module but related.
My guess is that side assist is locked out or disabled when the tailgate is open to stop the warning lights coming on if you open the tailgate with the engine running.
I think you may have a wiring fault or poor connection to the latch switch for the tailgate. There has to be some reason for the symptoms you are seeing and they all point to the latch switch.
My guess is that side assist is locked out or disabled when the tailgate is open to stop the warning lights coming on if you open the tailgate with the engine running.
I think you may have a wiring fault or poor connection to the latch switch for the tailgate. There has to be some reason for the symptoms you are seeing and they all point to the latch switch.
06-24-2016, 05:22 AM
#28
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Not the same module but related.
My guess is that side assist is locked out or disabled when the tailgate is open to stop the warning lights coming on if you open the tailgate with the engine running.
I think you may have a wiring fault or poor connection to the latch switch for the tailgate. There has to be some reason for the symptoms you are seeing and they all point to the latch switch.
My guess is that side assist is locked out or disabled when the tailgate is open to stop the warning lights coming on if you open the tailgate with the engine running.
I think you may have a wiring fault or poor connection to the latch switch for the tailgate. There has to be some reason for the symptoms you are seeing and they all point to the latch switch.
Thanks for all your help.
06-24-2016, 12:28 PM
#29
AudiWorld Super User
Here is a little snippet from an Audi tech bulletin - Of course it could simply be faulty bulbs in your tailgate light clusters - I would just swap out all four first and clean up the fittings - they get a bit corroded after a while.
Rear light switch-over sequence
The convenience system central control unit J393 receives sensor information from the convenience system central control unit 2 J773 for switching over the lights when opening the tailgate. Tailgate closed sender 1 G525 and tailgate closed sender 2 G526 are connected to the convenience system central control unit 2 J773. If the convenience system central control unit 2 J773 receives the information "tailgate open", this information will be relayed to the convenience system central control unit J393 via the convenience CAN bus. The convenience system central control unit J393 thereupon switches over from the rear light in the tailgate to the additional rear lights in the bumper. You will find information on senders G525 and G526 in the section on convenience system central control unit 2 J773 in this self-study programme. The convenience system central control unit is equipped with a cold and hot lamp monitoring system. This enables it to detect the failure of the brake/tail lights and turn signals. If the failure of a lamp is detected on one side of the vehicle, the system, switches over to the additional rear light
Rear light switch-over sequence
The convenience system central control unit J393 receives sensor information from the convenience system central control unit 2 J773 for switching over the lights when opening the tailgate. Tailgate closed sender 1 G525 and tailgate closed sender 2 G526 are connected to the convenience system central control unit 2 J773. If the convenience system central control unit 2 J773 receives the information "tailgate open", this information will be relayed to the convenience system central control unit J393 via the convenience CAN bus. The convenience system central control unit J393 thereupon switches over from the rear light in the tailgate to the additional rear lights in the bumper. You will find information on senders G525 and G526 in the section on convenience system central control unit 2 J773 in this self-study programme. The convenience system central control unit is equipped with a cold and hot lamp monitoring system. This enables it to detect the failure of the brake/tail lights and turn signals. If the failure of a lamp is detected on one side of the vehicle, the system, switches over to the additional rear light
02-21-2017, 04:30 PM
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