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I was replacing the side mirror puddle light last night and somehow ended up with both it and the turn signal not working any more. It's only on the one mirror, the other still works great. When I first plugged the bulb into the socket it tested fine but after I snapped everything back together, the turn signal and puddle light stopped working. The mirror is still able to move, and the auto-dimming and heating functions work as well.
Is there a fuse(s) that I should check? I ran through the list of fuses on the car but nothing sounded right and none of them looked blown after a cursory look. I'm planning on trying to take the mirror cover off again tonight and see what there is to see, though I don't expect much.
Thank you for those! I didn't know the door had a little panel that lets you access the door control module. Or if I did, I forgot.... I was really not looking forward to pulling the door panel off again. The turn signal PDF mentions a tab that needs attention when pulling off the cover, which may have been the missing piece.
I'll post an update when I get a chance to pull things apart tonight.
I have an iCarsoft scanner, but I doubt it has that level of access. I pulled the battery for about 30 seconds last night to see if that would help, but I will definitely pull it longer and see if that helps. It wouldn't surprise me if a module was just in a bad state.
I have an iCarsoft scanner, but I doubt it has that level of access. I pulled the battery for about 30 seconds last night to see if that would help, but I will definitely pull it longer and see if that helps. It wouldn't surprise me if a module was just in a bad state.
What did you have your controllers out for?
I am going to help you locate a bad connection or troubleshoot it. You've tried replacing the bulb already so now we can move on to consider other things.
Confirm the other side mirror light is on and power has not yet timed out...
Can you probe your pudleLt socket with a DVM to see what signal is missing (12V or GND)?
Is the socket in serviceable condition (moisture crusties)?
Is this a automatic folding mirror (broken wiring)?
Try gently wiggling the tiny wires at the connector end point (bad connection)
Remove the module out of the door and visually inspect it for oxidation or post sharp pictures.
As to why I had the door modules out... I am going through all ECU peripherals to simply eliminate trouble sources (capacitors, solderless pins, crusties, cold joints...) - I hate chasing my tail with random CAN glitches!
I am going to help you locate a bad connection or troubleshoot it. You've tried replacing the bulb already so now we can move on to consider other things. I pulled it out because I was swapping in an LED. When I tested it before buttoning everything up, it worked fine.
Confirm the other side mirror light is on and power has not yet timed out... Other mirror's turn signal and puddle light still work.
Can you probe your pudleLt socket with a DVM to see what signal is missing (12V or GND)? I'll check it out and see
Is the socket in serviceable condition (moisture crusties)? It seemed good enough. The inside looked fine
Is this a automatic folding mirror (broken wiring)? It's not an automatic folding mirror but it can be folded manually. I didn't fold it while working on it, but afterwards I folded it in and out a few times to see if it was a loose connection.
Try gently wiggling the tiny wires at the connector end point (bad connection) Will do
Remove the module out of the door and visually inspect it for oxidation or post sharp pictures. Definitely. I think I'll be doing this even if I resolve the problem elsewhere.
As to why I had the door modules out... I am going through all ECU peripherals to simply eliminate trouble sources (capacitors, solderless pins, crusties, cold joints...) - I hate chasing my tail with random CAN glitches! I don't blame you. My girlfriend's GL450 has a TPMS module that sometimes works, sometimes doesn't. After looking at your post, I'm going to pull it apart and see if it's as simple as a spot of solder. My wipers also have this habit of going nuts even when it's dry out. Now I'll be pulling that apart too at some point.
To pin-point the root cause, try to reinsert your good/old puddle bulb just for a quick sanity check...
There's a chance the controller output transistor needs a minimum current to latch-ON.
The circuit board only has a single relay to supply the power window actuator. That's how I known without a schematic that PuddleLt is controlled by a transistor.
Probe for voltage to figure which line shows issue.
Flaky TPMS:
So far I have not been able to locate this module near the rear axle... There are 90% chance it features the solderless male connectors.
It is likely hosted on the outside rather than inside for a better reception of 433MHz sensors.
The harness connector may allow water intrusion like its BlindSpot buddy does.
To help you sanitize your W212 car, deal with the R-SAM PCB and KeylessG modules as a priority. You will soon realize most solderless modules have easy access for quick service
+++++ furthermore : Clear DTC!
Try to clear the DCU faults with your original bulb inserted. Good chance the output control is logically disabled until reset.
Last edited by CaliBenzDriver; 11-02-2021 at 05:08 PM.
Last week ended up being eventful and I didn't have time to look into this until yesterday. What I found was, thankfully, simple. The non-working puddle light was because the bulb had become dislodged from the socket It must have gotten knocked loose when I was trying to get the socket into the housing. I put some grease on the socket before putting it in the housing, which made the process much simpler.
The turn signal didn't work because the light was burned out I probed its connector on the mirror and got a steady 12v. It was constant voltage, not the on/off voltage I expected when that light is blinking when you unlock the car. My best guess is the voltage is constant because it doesn't detect the bad light. Applying 12v directly to the signal light yielded no results. I have a new one on order, so we'll see how that goes.
I swapped out the puddle light on the other mirror with no problem.
Last week ended up being eventful and I didn't have time to look into this until yesterday. What I found was, thankfully, simple. The non-working puddle light was because the bulb had become dislodged from the socket It must have gotten knocked loose when I was trying to get the socket into the housing. I put some grease on the socket before putting it in the housing, which made the process much simpler.
The turn signal didn't work because the light was burned out I probed its connector on the mirror and got a steady 12v. It was constant voltage, not the on/off voltage I expected when that light is blinking when you unlock the car. My best guess is the voltage is constant because it doesn't detect the bad light. Applying 12v directly to the signal light yielded no results. I have a new one on order, so we'll see how that goes.
I swapped out the puddle light on the other mirror with no problem.
congrats on your puddle light socket! Whenever possible it's good practice to test things out before reassembling everything back up.
Regarding the blinker circuit... it likely works by switching GND instead of the positive side:
GND - Open - GND - Open -
✌️
Last edited by CaliBenzDriver; 11-08-2021 at 03:01 PM.
11-02-2021, 10:50 AM
I probed its connector on the mirror and got a steady 12v. It was constant voltage, not the on/off voltage I expected when that light is blinking when you unlock the car. My best guess is the voltage is constant because it doesn't detect the bad light. Applying 12v directly to the signal light yielded no results. I have a new one on order, so we'll see how that goes.
