Hi all, I've got a really confusing problem and I'm hoping someone can shed some light on this (no pun intended).

2019 Macan S, 60k miles.

A few weeks back my RH (passenger's side) low beam stopped working. DRLs and high beam work fine.

I decided to diagnose whether the problem was the headlight or the control modules.

Step one: Pulled both headlights out. Swapped the LED control modules from left headlight (known good) to right headlight (dead low beam). This is the square silver module attached to the bottom of the headlight.

Step two: Reinstall the headlights with the swapped modules and start the car. BOTH HEADLIGHTS WORK! Victory, or so I thought. I shut the car off after confirming full functionality of low beams, high beams, and DRLs. All is good.

Until I shut the car off. I started the car a few minutes later and the RH low beam was dead again. I swapped the control modules back to their original positions, and nothing changed. LH headlight is fine, RH headlight has no low beam. It doesn't make sense.

Fast forward a couple of weeks. I bought a slightly used headlight online. It actually looked brand new when it arrived.

I installed it, re-using the original modules (both LED control module and AFS control module). Started the car- RH low beam is still dead.

Just out of curiosity, I pulled the headlights again and swapped the LED control modules once again (the silver modules on the bottom of the lights). Re-installed the headlights, started the car. BOTH HEADLIGHTS WORK AGAIN! All functions are working as intended.

Until I shut the car off and restarted. RH low beam was dead again.

I'm stumped. It doesn't seem like a hardware issue. I know all of the LEDs are capable of illuminating.

Anybody have any idea what the problem could be, and how to fix it?

I have a dealer appt next week as a last resort. I'd prefer to fix this myself if I can figure out the root cause.

Thanks in advance for any help.

 

Is the car still under warranty with Porsche? If so, maybe you can convince the dealer that a headlight failure this early in the car's life is a factory defect.

With the sophisticated electronics systems in these cars requiring replacment parts to be "coded" to the car, perhaps this is the reason the hardware swap did not work (just guessing). Perhaps there is a fault further back in the car's control systems. Probably not a trouble shooting job for shade tree mechanics that don't have Porsche system scanners.

 

Unfortunately it's out of warranty. About the most I can do at this point is measure voltages at the headlight harness and compare L to R.

Failing passenger's side (RH) low beam seems to be a known failure.

 

I think you need to get the car scanned for fault codes. Unfortunately if the issue is related to computer control faults measuring voltages will not yield too much. I think you have proven the basic hardware is functioning.

 

@4strings I’m dealing with a similar issue on my 2017 Macan GTS. Were you able to diagnosis the issue you had earlier this year? I have the error “Check front right beam low light”. Also did a swap test for all of the electrical modules on the headlight to no avail. The failure code stayed on the front right beam. Now I’m starting to see other light warnings, like the front left turn signal. Not sure if these are all related. Next up I’m going to check the fuses and wiring harness (mice damage?). Let me know if you traced your issue!

 

Really? How odd. I guess it's another tip-of-the-hat to German electronics.

Could it be a bad ground? Or perhaps a corroded pin in one of the connectors?

 

Just happened to my wife's car with 25k miles. I swapped the modules and light sporadically comes in when car isn't running. But off for the most part. I'm debating if I should order a used headlight but saw that didn't solve anyone's problems. Appreciate the input

 

I ended up going through the below triage process and it finally fixed my issue. Also posted here with some images: https://www.macanforum.com/threads/2...t#post-2809855

Triage 1:
Reset error code with PIWIS. Warning error came back up as before.

Triage 2:
Swapped all (3x) electronic control modules from left->right and right-> left. Warning error remained with the front right light. Swapped all control boxes back.

Triage 3:
Checked all connectors, including back of headlight and bumper (under wheel fender liner at lower area). Removed connectors, blew out with air gun, checked for debris, reattached and confirmed ‘click’. Warning error remained the same.

Triage 4:
Purchased new headlight from service center. OEM 95B 941 040 L. Swapped over 3 electronic control modules (2 outside, and 1 inside light) and fan (twist-lock, not obvious how to remove initially). Warning error went away… success!

Ultimately the error followed the LED light itself and not any of the control modules. This appears to be a fully sealed light, so I’m not sure if it’s possible to repair. The part is crazy expensive ($3.2k ea). If anyone knows how to repair the light I’d like to do that for resale. Or… if anyone wants to buy the broken light (sans control modules and fan) I’d sell it for cheap.

Also, FWIW @dino buric I ended up replacing the other light too, since the new one was noticeably clearer than the 8-yr old one on the other side. So that means I have a fully functional (no error) used light from my 2017 Macan GTS (LED headlight). It’s the driver side if that’s helpful to you, I’d sell it for cheap.

 

Just to confirm my understanding, you spent almost $6500 replacing both headlights?

 

gulp yes. but hoping to make some $ back in reselling at least one used one and possibly figuring out how to repair the other.

 

Wow!! I'll now consider an extended warranty even more strongly when my CPO is up! That's just nuts!

 

Unless I am mistaken, the CPO warranty does not cover headlights.

 

True, headlights are a "wear item".

 

You have to purchase the "consumables" warranty. They are not covered under CPO or extended defects warranty. Consumables warranty also covers PSCB brakes, pads (and some other minor items like wiper blades). Well worth it for the headlight and PSCB coverage as these two items alone can be many thousands of dollars.

 

Lots of conflicting info about CPO coverage of the headlights on these forums. Some have had them covered, some insist they are not. Check with dealerships; if one ways no, move on to the next. Good luck!