2009 Rear Bulb - Problem & Question

[CZSteve]

Recently I've been having a problem with my Right / Rear tail light bulb; rec'd a warning that it was out via the EVIC and the expected fast blinking.
Changed it with a new bulb that night which did not fix right away; swapped the old bulb in and it worked correctly - confused but moved on.
Started receiving the same warning off and on; it'll self-correct after a bit - now it's dead again and other weird things...

- Turn signal: Flashes fast using the lower lumen / parking lamp filament; left works properly w/ the higher lumen filamant.
- Parking lights: Nothing lights up at all on right; left is normal.
- Hazard: Both flash - correct high lumen on left / wrong low lumen on right.

Plan on looking closer today to inspect socket & wires as best I can and change the bulb again.

- Suggestions on things to check other than a new bulb?
- Why does the Quad Head Light call for a 3057 bulb (6.7 watt) and the Dual Head Light model calls for the 3157 bulb (8.3 watt)? I have quad head lights.

EDIT: I have not modified or tapped into the wiring at all, this started out of the blue.

Thanks

 

[HeavyD]

Sounds like a bad ground.

 

[CZSteve]

I took time earlier to check the bulb; also checked the left light and found it had a 3157 bulb while the right was a 3057 - 8.3 watt VS 6.7 watt.
Put in a matching 3057 in the left and now the right works just fine.

I'm assuming it was a case of the computer detecting less resistance on the right against the higher watt left bulb.
Why did it just recently start w/ the error message? I can only surmise that the differential was on the bubble to begin with and over time the bubble broke as the filament aged - who knows and don't care as long as all is OK now.

I'm guessing if I put 3157's in both housings it would be fine.

 

[CZSteve]

OK - getting the bulb out error again; bulb is fine, it is a bit dimmer than normal.

Bad ground sounds like the most likely problem.
Can someone steer a novice regarding electrical in the right direction? Best to start w/ the bulb socket? Suggestions?

Thanks,
Steve

 

[HeavyD]

if you follow the wiring, it will come to where it is screwed to the box or frame - look for the black wire.