Rear Licence Number Plate Lights No Voltage

[JOHN220]

Hi, both rear number plate lights do not work on my 2005 C class estate. When the light switch is turned on the dash shows both lamps out. I have checked the lamp connections and there is no supply to them. All connections in the tailgate are o.k. Has anyone any ideas. Many thanks.

 

[television]

Hi, both rear number plate lights do not work on my 2005 C class estate. When the light switch is turned on the dash shows both lamps out. I have checked the lamp connections and there is no supply to them. All connections in the tailgate are o.k. Has anyone any ideas. Many thanks.

These are wired to the rear lights,, do not forget that a faulty ground wire will also turn them off

 

[colechelle]

sorry to disagree with you malcolm but i belive there wired to the rear sam! hence checking the wiring you we have to turn key off and on to see any flash of votage, rear sam see open curcuit and switches of live, same as a rear taillight bulb, if you dont switch the ign it still wont work with new bulb, be surpised if a wire broken all ready on a 2005 car!

 

[television]

sorry to disagree with you malcolm but i belive there wired to the rear sam! hence checking the wiring you we have to turn key off and on to see any flash of votage, rear sam see open curcuit and switches of live, same as a rear taillight bulb, if you dont switch the ign it still wont work with new bulb, be surpised if a wire broken all ready on a 2005 car!

I am pleased that you did disagree,, I have just noticed that its a 2005 car,, and thank you

 

[colechelle]

no problem malcolm, your not normally wrong on here!!

 

[piestore]

lights

HI
John220 you need to check voltage supply at positive terminal to the required lights, as already discussed rear SAM will try 3 times to light the lights and then shut off the supply until the next full ignition cycle (after CAN shut down) I would guess you have two blown bulbs or that the earth wire to the boot has broken at the hinge , this is common as the earth wire is a lot thicker than other wires in the loom, but you would also have problems with locking and opening the boot if this were the case

 

[JOHN220]

Problem solved thank you for your help.

I took the bulbs out to check for a supply to the lamp unit and did not know that the SAM unit would see it as a fault and shut off the supply.
Have found a pinhead size bit of corrosion inside one bulb holder, this must of been enough to change the resistance and give a fault. Thanks for the help on this forum.

 

[colechelle]

great news, a result and feedback to go with it!!