SL/R230: How do I get rid of fog light error code?
Thread Starter
Senior Member
Joined: May 2012
Posts: 263
Likes: 1
On my 3rd coupe!
How do I get rid of fog light error code?
I have a custom bumper with daytime running led's. They are wired to an ignition source so when the key is turned they come on. So the wires that ran to the fog lights are cut and capped off. The error message that my L & R bulbs are out is driving me nuts! Is there a way to code out the fog light option or something?
Super Member
Joined: Oct 2005
Posts: 997
Likes: 260
From: Frisco Colorado, USA
2024 GLB35 AMG, 2020 S560 Coupe
Just a guess, but here's a possibility. An onboard computer is detecting the open circuit and no test current flowing in the cut wires. You could either reconnect the bulbs with a grounded socket and mount them in an inconspicuous location or measure the resistance of the bulbs and insert an equivalent resistor from Radio Shack. You'd have to be careful to not turn on the lights and burn up the resistor or use a resistor that can handle the current and heat with a heat sink.
Thread Starter
Senior Member
Joined: May 2012
Posts: 263
Likes: 1
On my 3rd coupe!
Just a guess, but here's a possibility. An onboard computer is detecting the open circuit and no test current flowing in the cut wires. You could either reconnect the bulbs with a grounded socket and mount them in an inconspicuous location or measure the resistance of the bulbs and insert an equivalent resistor from Radio Shack. You'd have to be careful to not turn on the lights and burn up the resistor or use a resistor that can handle the current and heat with a heat sink.
Super Member
Joined: Oct 2005
Posts: 997
Likes: 260
From: Frisco Colorado, USA
2024 GLB35 AMG, 2020 S560 Coupe
I got out my handy Volt-Ammeter and measured 0.5 - 1.1 ohms on several different types of bulbs. I think you'd need a resistor of that value with a 300 Watt rating and a 24Amp fuse. (Note: I=V/R, P=V*V/R where V=voltage in volts, I=current in amps, R=resistance in ohms, P=power in watts) I think I calculated that correctly, but I don't have a lot of confidence in this approach.
Seems like your best options would be to simply install the original bulbs into a socket from Radio Shack connected to the original wires and grounded to the vehicle frame. You'll probably never turn on these bulbs with the dash switch and even if you did, there should be no problem if you mount the bubs in a protected area in the engine compartment.
Seems like your best options would be to simply install the original bulbs into a socket from Radio Shack connected to the original wires and grounded to the vehicle frame. You'll probably never turn on these bulbs with the dash switch and even if you did, there should be no problem if you mount the bubs in a protected area in the engine compartment.
Thread Starter
Senior Member
Joined: May 2012
Posts: 263
Likes: 1
On my 3rd coupe!
I got out my handy Volt-Ammeter and measured 0.5 - 1.1 ohms on several different types of bulbs. I think you'd need a resistor of that value with a 300 Watt rating and a 24Amp fuse. (Note: I=V/R, P=V*V/R where V=voltage in volts, I=current in amps, R=resistance in ohms, P=power in watts) I think I calculated that correctly, but I don't have a lot of confidence in this approach.
Seems like your best options would be to simply install the original bulbs into a socket from Radio Shack connected to the original wires and grounded to the vehicle frame. You'll probably never turn on these bulbs with the dash switch and even if you did, there should be no problem if you mount the bubs in a protected area in the engine compartment.
Seems like your best options would be to simply install the original bulbs into a socket from Radio Shack connected to the original wires and grounded to the vehicle frame. You'll probably never turn on these bulbs with the dash switch and even if you did, there should be no problem if you mount the bubs in a protected area in the engine compartment.
Trending Topics
MB World Stories
The Best of Mercedes & AMG
7 Craziest Things AMG Gas Ever Built
Verdad Gallardo
New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know
Verdad Gallardo
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
Junior Member
Joined: Feb 2013
Posts: 22
Likes: 0
From: Florida
2012 CL550 ; 2009 SL-550 Silver Arrow
Error code with LED fog lights
Not to worry - this is an easy fix. I replaced the OEM Fog Lamps on my SL550 recently. The ONLY thing you need to do is wire in line a 50w 6 ohm resistor behind each light. You may want to remove the lower valance to have better access. These resistors are readily available on line. You are probably going to have less than $10 in cost. One word of caution, these do get hot so do not attach them to a plastic surface. The reason for the resistor is because LED's send a different voltage signal to the computer. The resistor solves that problem.
Thread Starter
Senior Member
Joined: May 2012
Posts: 263
Likes: 1
On my 3rd coupe!
Not to worry - this is an easy fix. I replaced the OEM Fog Lamps on my SL550 recently. The ONLY thing you need to do is wire in line a 50w 6 ohm resistor behind each light. You may want to remove the lower valance to have better access. These resistors are readily available on line. You are probably going to have less than $10 in cost. One word of caution, these do get hot so do not attach them to a plastic surface. The reason for the resistor is because LED's send a different voltage signal to the computer. The resistor solves that problem.
