Only one reverse light, and no back up camera
11-01-2017, 09:31 PM
#1
Junior Member
Thread Starter
Only one reverse light, and no back up camera
So this vehicle I have owned now for two weeks, turns out the reverse light only works on the drivers side.
When I open the rear hatch, I noticed the yellow wire from the rear tail light harness has a stripped part and a long wire was twisted to it and ran to the other side of the car, and was next to the passenger side tail light harness, which had its yellow/black wire stripped.
I decided to twist it to this wire, and magically I have both reverse lights functioning, and the back up camera that wasnt working is now also working again.
Only problem is, the display on the dash now tells me I have a problem with the rear tail light, when I have them wired to each other.
Anyone have any ideas why it would only work when wired together... I know the bulbs etc must be working fine if they work wired togethger... maybe the one harness has a shorted or broken wire? Relay?
Thanks
When I open the rear hatch, I noticed the yellow wire from the rear tail light harness has a stripped part and a long wire was twisted to it and ran to the other side of the car, and was next to the passenger side tail light harness, which had its yellow/black wire stripped.
I decided to twist it to this wire, and magically I have both reverse lights functioning, and the back up camera that wasnt working is now also working again.
Only problem is, the display on the dash now tells me I have a problem with the rear tail light, when I have them wired to each other.
Anyone have any ideas why it would only work when wired together... I know the bulbs etc must be working fine if they work wired togethger... maybe the one harness has a shorted or broken wire? Relay?
Thanks
11-07-2017, 08:23 AM
#2
Super Member
Before your fix, did you get a dash warning that the passenger side reverse light was malfunctioning?
It is mostlikely the Sam module for rear lighting. When you hotwired it, the SAM now thinks the drivers side is drawing too much current.
An option would be to use a relay.(or FET transistor) so that the drivers side circuit only has to feed a low current relay coil to switch power to the passenger side. But then you also have to find power in the rear. Should be easy as you have the fuse box. If you want to keep the car a longer time... maybe get the sam replaced? yeah hundreds of dollars and needs to be programmed by StarSystem.
It is mostlikely the Sam module for rear lighting. When you hotwired it, the SAM now thinks the drivers side is drawing too much current.
An option would be to use a relay.(or FET transistor) so that the drivers side circuit only has to feed a low current relay coil to switch power to the passenger side. But then you also have to find power in the rear. Should be easy as you have the fuse box. If you want to keep the car a longer time... maybe get the sam replaced? yeah hundreds of dollars and needs to be programmed by StarSystem.
The following users liked this post:
imstock (11-08-2017)
11-07-2017, 09:32 PM
#3
Junior Member
Thread Starter
Before your fix, did you get a dash warning that the passenger side reverse light was malfunctioning?
It is mostlikely the Sam module for rear lighting. When you hotwired it, the SAM now thinks the drivers side is drawing too much current.
An option would be to use a relay.(or FET transistor) so that the drivers side circuit only has to feed a low current relay coil to switch power to the passenger side. But then you also have to find power in the rear. Should be easy as you have the fuse box. If you want to keep the car a longer time... maybe get the sam replaced? yeah hundreds of dollars and needs to be programmed by StarSystem.
It is mostlikely the Sam module for rear lighting. When you hotwired it, the SAM now thinks the drivers side is drawing too much current.
An option would be to use a relay.(or FET transistor) so that the drivers side circuit only has to feed a low current relay coil to switch power to the passenger side. But then you also have to find power in the rear. Should be easy as you have the fuse box. If you want to keep the car a longer time... maybe get the sam replaced? yeah hundreds of dollars and needs to be programmed by StarSystem.
Also, when i turn off the car and then turn it back on and drive around, there is no warning in the messages on the dash. It only comes back when I put the vehicle into reverse again.
It will then only stay while I am driving, but as soon as the vehicle is turned off and back on, it is no longer there.
11-07-2017, 10:08 PM
#4
Super Member
Yep, so the various light verification seems to work a bit differently. But no doubt the Sam verifies the light and is telling you it is defective on the drivers side when you connect the 2 bulbs. .
An alternative I just thought of would be a led replacement bulb. These draw far less current.... and my not trip the warning.
pretty sure its the sam.
you will need a 382 -aka P21W your local auto parts store will probably have some sort of led replacement.
something like this
An alternative I just thought of would be a led replacement bulb. These draw far less current.... and my not trip the warning.
pretty sure its the sam.
you will need a 382 -aka P21W your local auto parts store will probably have some sort of led replacement.
something like this
The following users liked this post:
imstock (11-08-2017)
11-08-2017, 05:00 PM
#5
Junior Member
Thread Starter
Yep, so the various light verification seems to work a bit differently. But no doubt the Sam verifies the light and is telling you it is defective on the drivers side when you connect the 2 bulbs. .
An alternative I just thought of would be a led replacement bulb. These draw far less current.... and my not trip the warning.
pretty sure its the sam.
you will need a 382 -aka P21W your local auto parts store will probably have some sort of led replacement.
something like this
https://www.amazon.com/PA-Backup-Reverse-Light-12V-Yellow/dp/B076JB772Q/ref=sr_1_1_sspa?ie=UTF8&qid=1510110345&sr=8-1-spons&keywords=382+led+bulb&psc=1
An alternative I just thought of would be a led replacement bulb. These draw far less current.... and my not trip the warning.
pretty sure its the sam.
you will need a 382 -aka P21W your local auto parts store will probably have some sort of led replacement.
something like this
https://www.amazon.com/PA-Backup-Reverse-Light-12V-Yellow/dp/B076JB772Q/ref=sr_1_1_sspa?ie=UTF8&qid=1510110345&sr=8-1-spons&keywords=382+led+bulb&psc=1
Last edited by imstock; 11-08-2017 at 06:25 PM.
11-08-2017, 09:04 PM
#6
Super Member
some generic info on SAMs
http://www.mercedesmedic.com/mercedes-sam-module/
these are expensive.. and you need the right one. So you have to check with the actual number on the SAM, or check with your dealer with your VIN
They are several hundred dollars and may need to be synced up the the main CANBUS with the Star system at your dealers.
If you are ok with the extra wire... well it may be an acceptable fix. Or like I said, try a led lamp!
i missed the part about the backup camera also now working... hmm gremlins...But the block diagram I have on ALLDATAdiy shows that the back up camera power supply is also connected to the rear SAM module. It would seem that the camera power supply is connected to the same wire as the passenger side backup light.
Sadly there is no detailed full electrical diagram of all light wiring.
http://www.mercedesmedic.com/mercedes-sam-module/
these are expensive.. and you need the right one. So you have to check with the actual number on the SAM, or check with your dealer with your VIN
They are several hundred dollars and may need to be synced up the the main CANBUS with the Star system at your dealers.
If you are ok with the extra wire... well it may be an acceptable fix. Or like I said, try a led lamp!
i missed the part about the backup camera also now working... hmm gremlins...But the block diagram I have on ALLDATAdiy shows that the back up camera power supply is also connected to the rear SAM module. It would seem that the camera power supply is connected to the same wire as the passenger side backup light.
Sadly there is no detailed full electrical diagram of all light wiring.
Last edited by efzauner; 11-08-2017 at 09:19 PM.
The following users liked this post:
imstock (11-08-2017)
11-08-2017, 10:09 PM
#7
Junior Member
Thread Starter
some generic info on SAMs
http://www.mercedesmedic.com/mercedes-sam-module/
these are expensive.. and you need the right one. So you have to check with the actual number on the SAM, or check with your dealer with your VIN
They are several hundred dollars and may need to be synced up the the main CANBUS with the Star system at your dealers.
If you are ok with the extra wire... well it may be an acceptable fix. Or like I said, try a led lamp!
i missed the part about the backup camera also now working... hmm gremlins...But the block diagram I have on ALLDATAdiy shows that the back up camera power supply is also connected to the rear SAM module. It would seem that the camera power supply is connected to the same wire as the passenger side backup light.
Sadly there is no detailed full electrical diagram of all light wiring.
http://www.mercedesmedic.com/mercedes-sam-module/
these are expensive.. and you need the right one. So you have to check with the actual number on the SAM, or check with your dealer with your VIN
They are several hundred dollars and may need to be synced up the the main CANBUS with the Star system at your dealers.
If you are ok with the extra wire... well it may be an acceptable fix. Or like I said, try a led lamp!
i missed the part about the backup camera also now working... hmm gremlins...But the block diagram I have on ALLDATAdiy shows that the back up camera power supply is also connected to the rear SAM module. It would seem that the camera power supply is connected to the same wire as the passenger side backup light.
Sadly there is no detailed full electrical diagram of all light wiring.
Did you have any suggestions on my issue with the airmatic?
https://mbworld.org/forums/r-class-w...tic-issue.html
I believe its out of calibration now, because I had one side jacked right up while working on it, and had the battery while doing so. Up until then, I didnt have any issues with any of the ride heights. But now the passenger side you can barely fit a finger between the tire and wheel well, yet the drivers side you can fit two clenched fists.
