G500 2003 headlight conversion
G500 2003 headlight conversion
MBWorld Fanatic!
Joined: Nov 2002
Posts: 1,028
Likes: 133
From: Massachusetts
2018 GLE350, 2014 G550, 2000 SL500, 1980 TR8, 1995 E320 Cabriolet
Despite the diode symbol on the case, these components appear (as near as I can tell from the pictures) to be wired in parallel with the bulb circuits which would make them reverse polarity protection diodes or clamping diodes. I've never heard of an install that requires those. If the new lights are LED, this makes me suspect that they are really load resistors to fool the SAM and prevent bulb-out errors. They could be a resistor with the diode in series.
If you unplug both of them, do the lights work, but give you a bulb out error? If so, I think that is what they are in which case you can just replace them with load resistors that are available on eBay and Amazon.
If you unplug both of them, do the lights work, but give you a bulb out error? If so, I think that is what they are in which case you can just replace them with load resistors that are available on eBay and Amazon.
Last edited by Floobydust; Aug 10, 2020 at 10:12 AM.
MBWorld Fanatic!
Joined: Nov 2002
Posts: 1,028
Likes: 133
From: Massachusetts
2018 GLE350, 2014 G550, 2000 SL500, 1980 TR8, 1995 E320 Cabriolet
If that is the case, then they are not load resistors. I downloaded your photos and enlarged them so I could see better and in one of them the diode seems to be providing some sort of switching function. It also looks like someone re-taped the lighting harness.
Are the the replacement lights halogen (incandescent), HID or LED? In one picture, there appears to be a standard halogen socket.
BTW, if you feel confident working with the wiring, you can just buy some 20 Amp diodes on Amazon and wire them in in place of the originals using crimp connectors or soldering. The band on the diode goes in the same direction as the cross on the diode symbol. Be sure they are well insulated so you don't get a short circuit.
Are the the replacement lights halogen (incandescent), HID or LED? In one picture, there appears to be a standard halogen socket.
BTW, if you feel confident working with the wiring, you can just buy some 20 Amp diodes on Amazon and wire them in in place of the originals using crimp connectors or soldering. The band on the diode goes in the same direction as the cross on the diode symbol. Be sure they are well insulated so you don't get a short circuit.
Last edited by Floobydust; Aug 10, 2020 at 02:03 PM.
MBWorld Fanatic!
Joined: Nov 2002
Posts: 1,028
Likes: 133
From: Massachusetts
2018 GLE350, 2014 G550, 2000 SL500, 1980 TR8, 1995 E320 Cabriolet
A 5 amp diode is just barely adequate for a 55 watt, 12 volt load, which could be why your original ones eventually burned out. I would use at least a 10 amp diode to make sure you are well covered from a power dissipation perspective. The cost difference is negligible.
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Joined: Sep 2020
Posts: 5
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1999 G500, 2003 330Ci
Were you able to resolve the issue with the 10 amp diode? I have the exact same problem where the diodes burnt out on one of those aftermarket headlights, also on the left side. After searching on internet they do not appear to be load resistors.
Thanks,
Leon
Thanks,
Leon
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