Both mirror turn signals "failed" simultaneously

Great Forum: First time I didn't find my answer searching existing threads! Took my 2010 Jetta to dealer for warranty repair of "Exhaust valve stuck open" (code P047 at 112,000 mi). Since it was due I asked them to do state inspection. They then say both mirror turn signals are not functioning, of course they want $334. Took it home and scanned with VAGCOM--it says both door controllers failed about 4000 mi ago, with exactly same time code and mileage. I found that the coding no longer included the exterior mirror turn signals, so I checked the turn signal box and hit "Do it", then got "Coding Accepted", but no luck, no signals. Any ideas???

VAGCOM Log File:
-----------
Address 42: Door Elect, Driver (J386) Labels: 3C0-959-70X-GEN4.clb
Part No SW: 3C0 959 701 B HW: 3C0 959 793
Component: TUER-SG FT 002 0307
Revision: 13101005 Serial number: 0000930868
Coding: 0004B5
Shop #: WSC 01383 790 50316
ASAM Dataset: EV_DCU42BroseDriveSide A03004
ROD: EV_DCU42BroseDriveSide_VW36.rod
VCID: 277327ED5EBC8320411

Slave Driver:
Subsystem 1 - Part No SW: 1K0 959 703 AH HW: 1K0 959 795 T Labels: 3C0-959-70X-GEN4.CLB
Component: J388__TSG-HL 006 1401
Serial number: 00000004921870
Coding: 000494

1 Fault Found:
67589 - Turn Signal in Exterior Mirror
B11FD 01 [009] - Electrical Failure
Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Reset counter: 206
Mileage: 180497 km
Date: 2046.14.26
Time: 15:54:21

-----------------
Address 52: Door Elect, Pass. (J387) Labels: 3C0-959-70X-GEN4.clb
Part No SW: 3C0 959 702 B HW: 3C0 959 792
Component: TUER-SG BT 002 0307
Revision: 15101005 Serial number: 0000913383
Coding: 0004B4
Shop #: WSC 01383 790 50316
ASAM Dataset: EV_DCU52BrosePasseSide A03004
ROD: EV_DCU52BrosePasseSide_VW36.rod
VCID: 287124D153A28C5848B

Slave Passenger:
Subsystem 1 - Part No SW: 1K0 959 704 AH HW: 1K0 959 794 T Labels: 3C0-959-70X-GEN4.CLB
Component: J389__TSG-HR 006 1401
Serial number: 00000004928302
Coding: 000494

1 Fault Found:
67589 - Turn Signal in Exterior Mirror
B11FD 01 [009] - Electrical Failure
Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Reset counter: 206
Mileage: 180497 km
Date: 2046.14.26
Time: 15:54:21

Wire(s) broken. Probably drivers door.

This is something new. Did they work before?

Yes, thanks, I thought I had noticed them working after the mileage of the reported failure--I knew I would be taking it in for state inspection.

See if they work with the four way flasher.

No, they don't work with the hazard flasher on. Replacements arrived today, I will test one before I take the door apart to check that side of the wiring harness for broken wires.

Both left and right sides had the inboard LED blown, both outboard LEDs on both sides still work fine when powered up. Diodes on little pc boards are fine. And VAGCOM says both blew at the same time...go figure. Anyway replaced and work fine--BUT right side mirror spring mount has corroded all the way through and would have fallen off if not for the housing. It is white corrosion as others have reported elsewhere.

That is a odd one.