chaadster

Good Folk,

Based on my own experience and the contacts I've received from others, I thought it would be useful if we had a "master thread" (of sorts) where we could compile our collective wisdom with regards to LED replacement bulbs in our cars.

My hope here is that those who've made the change to LEDs will list which bulbs they used where, so that those who follow may benefit from those who've gone down this road already.

Thanks, in advance, to those who contribute.

chaadster

On my '88:

1. Courtesy lights (doors, hatch, overheads)--39mm, 6 led, festoon bulbs
2. pod switches-- #74 wedge base bulbs
3. shifter indicators on console-- 44mm festoon, I think 8 led. I drew power from cigarette lighter.
4. HVAC control head-- #74 wedge base, wide angle (flat head). Not perfect, because it's a little dim, and provides little light to the sides to illuminate the fiber optic threads for fan speed and sliders. There's a 3 led, #74 from www. autolumination.com that may work better than the single, wide angle bulb.
5. door marker lights (the red squares on the trailing edge)--BA9 bulb

I've done everything in red, and I like it.

danglerb

picts

Jadz928

Interior dome/door lights - 44mm 9 LED Festoon
Glove box light - 31mm 9 LED Festoon
Door marker lights - Ba9 Bayonet Base Frosted Led Bulbs RED

borland

https://rennlist.com/forums/showthre...safety+borland

UKKid35

I've used 44mm festoon bulbs, they seem a very tight fit. The cool white light is very different in character to the orginals which are much warmer. Overall I'm very pleased as my main aim was to reduce the chance of killing my battery when leaving the car doors open.

ew928

Search for 42mm festoon LED bulbs on Ebay.
I've tried one of the high power ones and if fits a lot nicer than the 44mm ones.
No more metal bending to get the 44mm bulbs in.

Turned all my interior lights off when it killed the battery once.
Now I've got them all switched back on. It's nice seeing the interior at night.
Didn't realize there was a courtesy light in the back hatch for the longest time.

Ernest (NYC)

BrianG

I have tried replacing the exterior bulbs of my '87 S4, but have found that every one of these attempts has resulted in a bulb monitor "failure" indication.

I seek a method of circumventing this monitoring system since LED lamps will be essentially permanenent.

chaadster

I'm sure you could disable the Lamp Monitor, but it seems like something nice to have, unless you've replaced ALL of the exterior bulbs with LEDs, which, if I understand correctly, almost never burn out.

I have also seen in-line resistors that can be installed to trick the Lamp Monitor into seeing the correct current. Of course, that also means you lose the energy efficiency of the LEDs...

Also on the negative side, as Alan has pointed out in other threads, acheiving the same level of performance with LEDs as with incandescant bulbs is very costly, and unless you just absolutely-positively-have-to-have-LEDs, they are a poor alternative to cheap, standard bulbs.

Which LED replacements have you tried, BrianG? Did you like the results?

Popo928

I just got 3 39 mm festoons from www.autolumination.com in red. Look very nice but I had to bend the tabs in a little to make them fit tight. If I did it over again, I'd do 41 or 42 mm ones.

BrianG

Circumventing the light-monitor system is more difficult than it sounds. All of the light wiring goes into the "box", and the lights do not function with the box removed. I have no pin-out information regarding the box, so jumpering that plug is going to be totally hit and miss, and I fear "burning" something up in the harness.

I have tried a number of 1186 and 1187 replacement LED units. I like the look of them, especially the brighter rear running-light lamp. If I could circumvent the monitoring system, I would also embed another LED array or two in the reflector units as well.

Alan

Brian,
You can add ballast resistors to LED bulbs to cause them to consume the same total power as the bulbs they replace. Look on ebay, match for the wattage of the bulb you are replacing. I have done this for my rear central brake light (along with a pulser module). I would not personally replace any other external lights with LED's for reasons I've mentioned before... but you can with this method. The ballasts consume a lot of power - so they get hot and need a metal to metal connection to dissipate. Of course this makes the LED + ballast no more efficient than the bulb they replace. It also means that the bulb monitoring unit will now warn you of a failure of the ballast resistor but not of the LED bulb. To me this is an unaccepable trade-off unless there is significant other benefit to be had - hence my views.

Most automotive bulbs are fairly reliable, cheap and easy to find and work well in the fittings that were designed for them....

2 aspects of LED bulbs that could be most interesting are: efficiency and instant response (brightness is usually not a real benefit - and we can't get the efficiency except on unmonitored circuits...

BTW cheap LED bulbs (read no brand Chinese imports - esp. 'superbright') may NOT be that reliable since they may be overstressed to get high luminous output - but they do typically burn out progressively - since they are actually arrays of LED's that die one by one.

Alan

BrianG

Yes, Alan, I accept your observations and opinions about LED lamps.

All except the appeal of the BLING factor!

steaditim

So if adding ballast resistors to LED bulbs will cause them to consume the same total power as the bulbs they replace, doesn't that defeat the purpose of not draining the battery if you leave a light on?

Alan

Yes - but for the interior lights there is no bulb monitoring so they are useful there - those are probably also more likely to be left on since the car should chime to warn you of any exterior lights left on...

Alan