As I search for a replacement P21/4W bulb for my 997.1's rear left brake light, I see lots of LED alternatives that claim to "fit".

There are a lot of threads on this forum about replacing the entire light assembly with an aftermarket LED assembly, but I see nothing about rear parking, brake, and turn-signal LED bulbs.

Is it possible to replace some of these exterior incandescent light bulbs on our cars with equivalent LED bulbs?

I would expect that most LED bulbs would generate CAN BUS error codes, but I also see some LED replacement bulbs advertised as "CAN BUS ERROR FREE", and some even claim to have "built-in" resistors.

A few benefits of being able to use LED alternatives would be:

1. Get faster LED light-up reaction times (for driving safety).
2. Get brighter LED color (for driving safety).
3. Cheaper than going with an aftermarket assembly just to get benefits of #1 and #2.
4. Get to keep your stock "look".
5. Take advantage of newer technologies. (I'm sure incandescent bulbs will eventually become rare to find).

Has anyone tried to replace the incandescent bulbs with LED alternatives?
Do they work?
If so, can you recommend some (particularly 12V P21/4W)?

 

Short answer is no. You would need so many resistors (to avoid errors and overloading the LEDs) and ultimately, the LED "bulbs" would provide very little visual difference vs. incandescents in the stock housing.

If you want a "better" but still OEM look, get the stock all red tails. You can find them used on here or other sites every so often ($250-$450 typically).

 

Thanks.
This is good to know, since LED replacement bulbs are sold everywhere now, and most claim to be "compatible" with our cars or are advertised as "error free."

 

I wanted to match the color of my position lights with the headlights. I got LEDs from autozone which triggered warning light. Then replaced them with can bus LEDs which i found on superbrightleds website and they work great! Good color match and no warning light. I can imagine you can do the same with other bulbs.