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Discussion Starter · #1 ·
Just wanted to post about a successful turn signal bulb upgrade.

I've tried several ebay units which replace the entire turn signal, but they seem to be universally too dim and just crap quality overall.

So instead I just upgraded the bulbs themselves to LED units, and kept the stock housings.

I tried the iBrightstar bulbs (BAU15S, i.e. 150 degree stubs) on amazon ($17 per pair) and they are exactly what I was looking for, way brighter than the OEM bulbs!

Installing one front LED bulb (with the rear still a stock incandescent bulb) caused them to flash very fast, which I had expected, but I was surprised to find that installing both front and read LED bulbs caused that signal chain to flash even slower than stock. Either the ECU or the iBrightstar bulbs are somehow compensating for the lower current draw, but the result is just too slow (I'd prefer faster than stock anyway).

I then tried bypassing (i.e. placing in parallel) the circuit with various different resistors values, from 12 ohm all the way up to 10k ohm, and I found that any resistance below about 4.7k appears to put the circuit back in "incandescent" mode, and you can dial in the flash frequency by changing the resistor value (lower resistance = faster flash rate).

4.7k was just baaaarely faster than the stock bulbs, 2.2k was a bit faster than that, and by the time I got to 1k, that was almost as fast as it gets (i.e. there was only a tiny difference in speed between 1k and 12 ohm).

A 1k resistor at 14.4V burns about 0.21 watts, so we can just use a common 1/4 watt resistor, which means we can get away with soldering one directly to the socket in the OEM housing, very convenient!

Here's a video comparing the OEM bulbs to the iBrightstar + 1k resistor:

Here are some photos of the resistor mod:

Automotive lighting Hood Motor vehicle Asphalt Bumper

Automotive lighting Motor vehicle Vehicle Jewellery Automotive exterior

Body jewelry Automotive lighting Liquid Art Automotive design
 
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