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Lou P. master tech
Lou P. master tech, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3723
Experience:  15 years master certified 100% fix rate and have access to factory radio codes, wiring, and instructions.
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MY 3RD BRAKE LIGHT, AND LICENSE PLATE LIGHTS QUITE WORKING..

Customer Question

MY 3RD BRAKE LIGHT, AND LICENSE PLATE LIGHTS QUITE WORKING.. THE PLATE LIGHT CAME ON AND OFF SAME WITH BRAKE LIGHT. LOSE WIRE
JA: Have you checked the brake light switch? How about the fuses?
Customer: IS THERE A FUSE FOR THESE ITEMS? AND WHERE
JA: What is the model/year of your Mercedes?
Customer: 2003 SL 500.. They intermittent.. plate light came on and off.
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: I don't have a fuse diagram which tells where it is, in trunk or under hood.
JA: Anything else you think the mechanic should know?
Customer: and which one?
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Mercedes Mechanic about your situation and then connect you two.
Submitted: 5 months ago.
Category: Mercedes
Customer: replied 5 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 5 months ago.
OK I AM WAITING.. OTHERWISE CALL ME.(###) ###-####
Customer: replied 5 months ago.
still waiting
Expert:  Lou P. master tech replied 5 months ago.

Hello sorry for the delay. I'll send a phone call offer over if you are interested. If not we can chat here. It's most likely a broken wire that rides up the hinge area to the trunk lid, have you removed anything so far or tried any repairs ?

Customer: replied 5 months ago.
when I moved the trunk up and down.. by hand of course.. the plate lites came on. when it was close to shut, they went off.are the 3rd brake lamp and plate lites run together?
Customer: replied 5 months ago.
I will need to dis- assemble the harness on the hinged frame to trunk? and follow wires?
Customer: replied 5 months ago.
I guess trace the wires. into trunk past hinges? and run new wires? solder together and put heat shrink?
Expert:  Lou P. master tech replied 5 months ago.

First thing I would do is trace the wires by wiggling the wiring

Expert:  Lou P. master tech replied 5 months ago.

Since we know it is affected by moving the trunk it will have to be at a position where the wires bend and flex near a hinge.

Expert:  Lou P. master tech replied 5 months ago.

And yes all the trunk wiring runs together. It may be a ground wire affected since there are multiple issues with the trunk electrical.

Customer: replied 5 months ago.
okay.. I released the wiring harness from trunk hinge, removed all tie wraps.. 3 brake lite works now.. but no plate lites.. they did earlier intermittently.. is there a fuse? if so where?
Customer: replied 5 months ago.
otherwise I will get some wire, and my 12 volt tester and find a live wire the works with lights on, and tap into? might be easier..
Expert:  Lou P. master tech replied 5 months ago.
There is no fuse. It's all control module controlled.
Expert:  Lou P. master tech replied 5 months ago.

And no don't tap into. Let me check a wiring diagram and tell you what wires work the lights. You check both hinges ? There may be wires in both sides

Customer: replied 5 months ago.
ok
Expert:  Lou P. master tech replied 5 months ago.

Ok here is the diagram. Also make sure you turn the headlight switch off and cycle the key or else the lights won't work. The module will kill the circuit if it senses a open circuit. I will explain the diagram

Expert:  Lou P. master tech replied 5 months ago.

E19/1 and E19/2 are the lights. The brown wire is the ground. So since the third brake light works now that means ground w6/1 is ok. And the odds of having 2 power wires broken are possible so find and trace the grey wire with violet stripe and the other wire is a green wire with blue stripe. Do you see what I am referring to ?

Expert:  Lou P. master tech replied 5 months ago.

Hello Ben., i have not heard from you since yesterday, did all go well? did you need more assistance?