License plate light
04-16-2010, 10:44 PM
#1
Member
Thread Starter
Join Date: Apr 2008
Location: So. Cal (Orange County)
Posts: 93
Likes: 0
Received 0 Likes
on
0 Posts
CLK 55 AMG
License plate light
The left bulb on my license plate light keeps going out. I've changed it twice in the past 3 weeks. Would anyone know why it keeps blowing out the blub? I first thought it was the bulb but know I'm thinking its something else, except I have no idea what would be causing it.
04-17-2010, 09:10 AM
#2
MBWorld Fanatic!
Bulbs are rated in watts (e.g. voltage x current) and the fact that it is only this bulb leads me to believe the power electrical system is still providing the proper voltage (e.g. over voltage will burn out a bulb).
If the proper voltage is applied, by ohms law (e.g. E = I x R), the resistance of the filament determines how much current is drawn. The power used would be P = E^2 / R or I^2 x R.
If the 'light defective warning' is coming on, it sensed incorrect power (e.g. current) being drawn (e.g. burned out or a filament drawing the wrong current).
First verify that the right bulb part number is being used.
Then determine if, when the warning appears, if the bulb is actually lit to normal brilliance, dim or dead.
If the later two, I would suspect a defective in the replacement bulbs (e.g. wrong filament material, poor contact with end connections)....in which case, I would try another brand or source of supply (has a bad batch).
If the proper voltage is applied, by ohms law (e.g. E = I x R), the resistance of the filament determines how much current is drawn. The power used would be P = E^2 / R or I^2 x R.
If the 'light defective warning' is coming on, it sensed incorrect power (e.g. current) being drawn (e.g. burned out or a filament drawing the wrong current).
First verify that the right bulb part number is being used.
Then determine if, when the warning appears, if the bulb is actually lit to normal brilliance, dim or dead.
If the later two, I would suspect a defective in the replacement bulbs (e.g. wrong filament material, poor contact with end connections)....in which case, I would try another brand or source of supply (has a bad batch).
01-30-2015, 11:59 PM
#3
Member
Join Date: Jul 2012
Location: Charlotte, NC
Posts: 91
Likes: 0
Received 3 Likes
on
2 Posts
10 C63/p31, 84 190/5.8L, 14 Audi Q5 TDI, 03 Suburban /8.1, 87 Porsche 944/358" 77 Ferrari 308 Dino
Defective LEDs....
My left one also has given problems. When the lights are first turned on, the left one blinks slowly and then doesn't work. It is connected to a very strange and complicated system using what is called a SAM. It is located behind the trunk lining in the rear left wheel well in my 05 C55. If the system detects a problem, it shuts off the voltage! It apparantley detects incorrect lamps installed.
The next time your bulb (lamp) 'burns out' swap it to the right side and see if it actually is burned out. I recently pulled everything out of the trunk on the left side to check the wiring and to access the SAM. All looked good so I pulled the plug for the license cable and reseated it and it now works fine. For how long, I don't know, but they both work now.
Many of the recent MBs have this problem and heard you may take it to the dealer to be scanned. I have also seen SAM rebuilders on the web that repair them and give a warranty....some for as long as you own the vehicle!
Good Luck!!
The next time your bulb (lamp) 'burns out' swap it to the right side and see if it actually is burned out. I recently pulled everything out of the trunk on the left side to check the wiring and to access the SAM. All looked good so I pulled the plug for the license cable and reseated it and it now works fine. For how long, I don't know, but they both work now.
Many of the recent MBs have this problem and heard you may take it to the dealer to be scanned. I have also seen SAM rebuilders on the web that repair them and give a warranty....some for as long as you own the vehicle!
Good Luck!!
01-31-2015, 10:09 AM
#4
MBWorld Fanatic!
How is the trunk lid liner removed?
After removing all the plastic pop rivets, the lining around the latch and trunk light switch breaks free. However, to the right of the latch, the lining around the trunk release plunger does not break free and allow the lining to be removed.
None of the lights on my trunk lid work (parking, backup lights) and I need to access the wiring to check for a ground fault.
Initially the check lamp warning occasionally turned on when braking. Recently, after opening/closing the trunk, the check lamp warning turns on every time I apply the brakes.
Additionally, when I open the trunk, after the engine is off, a couple of other devices also operate (e.g. outside side mirrors). If I open the truck while the engine was running but then shut off, the electric radiator fan runs at full speed. If I open the trunk while the engine remains on, all of the above plus my dashboard lights up and flashes like a XMAS tree.
After searching, these same symptoms are usually due to a ground fault (e.g. typically a broken ground wire / connection within the trunk lid or hinge harness).
After removing all the plastic pop rivets, the lining around the latch and trunk light switch breaks free. However, to the right of the latch, the lining around the trunk release plunger does not break free and allow the lining to be removed.
None of the lights on my trunk lid work (parking, backup lights) and I need to access the wiring to check for a ground fault.
Initially the check lamp warning occasionally turned on when braking. Recently, after opening/closing the trunk, the check lamp warning turns on every time I apply the brakes.
Additionally, when I open the trunk, after the engine is off, a couple of other devices also operate (e.g. outside side mirrors). If I open the truck while the engine was running but then shut off, the electric radiator fan runs at full speed. If I open the trunk while the engine remains on, all of the above plus my dashboard lights up and flashes like a XMAS tree.
After searching, these same symptoms are usually due to a ground fault (e.g. typically a broken ground wire / connection within the trunk lid or hinge harness).
