papak Posted March 24, 2018 Share Posted March 24, 2018 I have found that the incandescent rear directional bulbs are melting the plastic lense covers on my Birkin. I naturally switched over to LED 1156 bulbs. The directionals operate normally with the incandesants but flash simultaneously (but at the normal rate) with the LEDs. I am using Phillips LEDs which are supposed to be ballasted to work correctly as retrofits. The flasher relay is labeled for LED use (CF14 JL-02, 12v 0.02A-20A). I see that the common problem is a rapid flashing rate with the retrofits, fixed by either installing ballasts or replacing the flasher relay with an LED compatible one. I'm left a bit perplexed. Any suggestions other than replacing the flasher relay? Link to comment Share on other sites More sharing options...
xcarguy Posted March 25, 2018 Share Posted March 25, 2018 papak, I have LEDs at all four corners and no issues. Using this from Painless: https://www.summitracing.com/parts/prf-80230?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-painless-performance&gclid=EAIaIQobChMIp9OQ0I2G2gIVCztpCh1ULQ4zEAQYASABEgJ0mfD_BwE I'd suggest changing the flasher first. Link to comment Share on other sites More sharing options...
papak Posted March 25, 2018 Author Share Posted March 25, 2018 I spoke with Tom Carlin and we determined that the common wire for the directional indictator light is the problem. Disconnect that and all is well. The front indicators on the Birkin are already LEDs with their own integral ballasts. The flasher relay is designed for LEDs. It is a three prong relay while the Painless one is four prong. Link to comment Share on other sites More sharing options...
xcarguy Posted March 25, 2018 Share Posted March 25, 2018 Glad you got it sorted. And I must’ve sent you the wrong link; FWIW, my Painless flasher is two prong. Link to comment Share on other sites More sharing options...
wemtd Posted March 26, 2018 Share Posted March 26, 2018 He really is a wealth of knowledge and very helpful on the phone. Link to comment Share on other sites More sharing options...
papak Posted March 31, 2018 Author Share Posted March 31, 2018 (edited) I finally got to the bottom of my problem. The classic problem that arises when converting from incandescents to LEDs is rapid flashing of the commanded bulb. This is caused by insufficient resistance in the selected circuit. This was not my problem. In my case, when the directional was activated, after switching to LEDs, all four lights would flash simultaneously with the selected directional flashing a bit brighter. When I removed the scuttle today, I discovered that the problem was with the manner in which the indicator light was wired. The first step I took was to disconnect the leads from the indicator light. Everything worked perfectly! It turns out that the Birkin wiring harness and wiring diagram has two wires connecting to the indicator, a combined lead from the left directionals and a combined lead from the right side. The amount of current transferred across the indicator light isn't enough to trigger the offside bulb when using incandescents. There seems to be enough resistance in the circuit to prevent offside flashing. The problem only arises when using LEDs due to their much lower draw. There are two ways to resolve the problem, the first is to wire a resistor into the 12v lead to each rear directional LED. The other solution is to wire a pair of diodes into the leads to the indicator light. I found the necessary parts for both of these at www.superbrightleds.com under LED accessories. The resistors have heatsinks on them. The diodes come fabricated into a "Y" lead (Metric Bike Diode Kit MDK-1, $2.99). The resistors were similarly priced. The other factor to consider is the LEDs themselves. There are a lot of inexpensive ones on the market (mainly Chinese) most with inconsistent voltage requirements. The ones to get are the Philips Ultinon bulbs in 1156 and 1157 sizes. The run about $25 each from Pep Boys and others but they are worth it. The are correctly engineered. They use 12v and produce 42 lumens of brightness at 6000k. They come in white, red and amber and are designed to withstand the vibration levels we experience in these cars. They are also internally ballasted so the current draw works with the standard flasher relay. The front directionals on my car are small LED modules with an internal ballast. These came with the car and didn't contribute to the problem. Hope this helps the next guy who runs into this. Edited March 31, 2018 by papak Link to comment Share on other sites More sharing options...
wemtd Posted March 31, 2018 Share Posted March 31, 2018 I must be getting old.. Reading your solution jogged my memory to last year when I installed LED rear light clusters and had the same problem. Same solution with diode installation (similarly inexpensive trailer diodes from napa) - totally forgot about this fun discovery. Link to comment Share on other sites More sharing options...
papak Posted March 31, 2018 Author Share Posted March 31, 2018 Don’t feel bad. It took me a while to think clearly about it and figure it out. Probably wouldn’t have taken so long 30 or 40 years ago. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now