Case Study: 2008 A6, more screwy bulb games....

[Jef]

Lights bulbs... what they are and how they are installed matters!

2008 A6, has tail light issues in the CCM:

4 Faults Found:
02742 - Bulb for Brake/Turn Signal Light; Left
009 - Open or Short to Ground

02743 - Bulb for Brake/Turn Signal Light; Right
009 - Open or Short to Ground

01506 - Bulb for Rear Fog; Right (L47)
009 - Open or Short to Ground

01518 - Bulb for Back-Up Lights; Left (M16)
009 - Open or Short to Ground

I don't know what all the back story on this car is, but they just installed a new from dealer CCM due to the tail light issue. As I understand it, the CCM was replaced because of the tail light issues. Shop finds powers and grounds for CCM to be good, wiring from CCM to tail lights is good, but the CCM is only providing "3 volts" to the bulbs. CCM part number and coding looks to be spot on for this VIN.

Are there aftermarket bulbs in this thing? No, looks like normal bulbs, all light up it given power/ground.

OK, new CCM, no wiring issues, crap bulbs can be an issue.... using the wiring diagram, we ID the Rear Fog, Right (L47) bulb. Now take that bulb and install it on the left side, and left side bulb to the right side. Clear codes... and now the fault code changes to 01502 - Bulb for Rear Fog; Left (L46) Open/short to ground.

Taking a closer look at the bulbs... no marking on them to be found, look to be very generic bulbs.... C.R.A.P. is my guess. As per PL24, these should be common P21W bulbs (4x) and PY21W (1x) per tail light. Get all new known good brand bulbs.... cheap investment after buying a CCM.

[Jack@European_Parts]

If not Flosser, Narva, Hella or Osram... gonna have a BAD time!