finally!

Looked through threads though could not find definitive suggestions on which LED turn signal bulbs to use for front and rear and what relay(S) to get...

Anyone?

Ed Scherer

I'd recommend (and have recommended ):

• Super Bright LEDs 1156-A45T (if amber needed) bulbs or 1156-R45T (if you've painted your turn signal lens area red) bulbs for the rear turn signals;
• Super Bright LEDs 1157-A45T bulbs for the front turn signals;
• Super Bright LEDs CF13GL-02 flasher relay;
• Super Bright LEDs RL-2525 load resistors: one in parallel with each of your rear turn signals if you discover that the turn signal indicator light in your instrument cluster doesn't light properly after converting to LEDs

Nicole

I have sold many LED kits for the front turn signals and the side markers. However, when I tested LEDs in the rear turn signals, I came to the conclusion that converting them is not worth the trouble.

Everything worked fine when I turned on the emergency flashers (all four corners flashing). But when I used the turn signals (one side flashing), the LEDs never turned off entirely. The "flash" was from bright to dim, rather than bright to off.

I concluded that one would have to install resistors in the back to mimic the regular bulbs - but where to put those resistors? They can get hot, so you can't put them just anywhere.

Given that you really can't see a difference through the 928s amber rear turn signal lenses, I decided not to pursue this any further.

BTW: My kit for the front includes LEDs that are different from the ones Ed recommends - mine are completely clear and invisible when off. My kit retails for $34.98 - Today is the last day of my Labor Day sale, so you can save 10% and get the whole kit for little more than one of the bulbs Ed recommended. Use promotion code LD2011P10.

77tony

Ken, If you are to do the blinkers, only do the fronts, or just the rears. Otherwise you will have to install resistors, and you will lose your blinker dash light if you do all 4 four corners. IIRC, you already wired all of your rear lights in a series along with your brake lights, so if you were to do them, only do the fronts 02. 77Tony

Ed Scherer

Don't fear the load resistors.

I recommended what I recommended for a reason. It works, and I've done exhaustive comparisons of lots of alternatives.

Shown below is a right side tail light assembly with 25 Ω load resistor affixed with strong exterior-rated two-sided tape. It's been working for a long time (long enough that I don't remember; a few years).

25 Ω in parallel with each rear turn signal bulb is all you need to make everything work. 25 Ω doesn't dissipate as much heat as the 6 Ω load resistors (but is enough to get the job done), so heat hasn't been an issue.

Nicole

This looks good, Ed! Thanks for sharing.

77tony

Ed, I think Ken has already performed the "Brake light upgrade" https://rennlist.com/forums/928/4551...grade-mod.html that being the case, would you now need to wire resistors on the six individual LED tailamps ? Would your dash indicator blinker light still be visible ? TIA. 77Tony

finally!

Confused, you are saying to use RED bulbs for the turn signals if I have painted my rear lights red?

Ed Scherer

That mod is related to brake lights only (but there are still issues to be aware of).

Keep your thinking about brake lights and turn signals separate.

• For turn signals, the "complications" in the 928 that occurs after replacing the turn signals with LEDs are two-fold:
  • If you don't replace the flasher relay, you'll probably get "hyperflashing" (fast flashing) due to the similarity between the high-resistance (and thus low current draw) of LEDs and a burned out incandescent bulb. This is easily dealt with by replacing the flasher relay with a CF13GL-02 or similar. This could also be solved by using a load resistor (ideal value would have to be calculated based on specific LEDs used) in parallel with each turn signal LED, but I don't advise this.
  • The other problem that you will probably notice that the turn signal indicator light in your instrument cluster doesn't light properly anymore. A 25 Ω load resistor in parallel with each rear turn signal 1156-style LED lamp should fix that problem.
• For brake lights, the "complication" that arises after replacing the brake lights with LEDs is that the cruise control stops functioning; borland was (I believe) the first person to both note this and offer a solution; see Cruise Control Mod for LED Brake Lights. Now, answering your question, if you have done the "S4/GT/GTS Brake Light Upgrade Mod", you would not need to put a load resistor in parallel with each of the six brake light LEDs because they're already wired in parallel. You would, however, need to do something to address the cruise control issue. You could either do borland's Cruise Control Mod for LED Brake Lights, or I'm pretty sure that you could add just one 6 Ω (25 Ω might even work, for reduced current flow and thus reduced heat dissipation, but I haven't tried it yet) load resistor in parallel with the brake light LEDs on each tail light assembly.

Note: a 6 Ω load resistor powered continuously gets very hot (too hot to touch for long); if you use them, use them with care and place them carefully to assure they can cool and won't melt anything. The 25 Ω load resistor used as I showed with the turn signal circuit doesn't get as hot (it has less power to dissipate and it's only powered half time maximum anyway in the flasher application).

Also, I disconnected the two signals (one for parking/marker light failure and one for brake light failure) that the bulb control module sends to the instrument cluster. See the post "The easy way to defeat the bulb control module on an S4 (and later?)"; other methods for accomplishing this are also discussed elsewhere in that thread.

Yes. Generally, you should put the same color LED behind a lens as the lens color. If you've altered that lens color (e.g., painted it red and "converted" it from amber to red), go with the color that you want to be predominant—in this case, red.

jsherid1

On my 87, the cruise still functions after the LED upgrade. I do have to modify the system to defeat the bulb control module. Turn signals are next.

finally!

My question was simply related to TURN SIGNALS, already painted the tail housings red and did the brake light LED upgrade along with mod for cruise control and after converting 3rd brake light to LED added a resistor so the cruise works fine.

Since the turn signal is supposed to be yellow that is the color LED I will go with so it shines yellow through the OEM yellow plastic which has been painted red.

Thanks for the info guys!

Alan

Go with Ed's proposal (RED). The orange housing filters 'white' light from the bulb to mainly orange, your red paint filters the orangy light down to just the red. LED's don't have as wide a spectrum of color - on an orange LED once you filter everythig out that isn't red there isn't much left. Start with just the color you want to end up with - you will lose less on the way through the 2 filters you now have (Orange -> Red)

Alan

U-928

Blowing some dust off.

Ed, do you know if the relay you spec in your post would work in an OB application?

I've got a in-op LF turn signal, but the car thinks it operates as it should, the inside blinker indicator is normal speed.

I bought (4) the 1156-A18-T (amber 18 SMD) for the blinkers thinking that it would maybe resolve the issue. It didn't, and as you've stated correctly, now they don't function at all. So I'll put normal bulbs back in and have to dig deeper into the non-functioning LF signal...

Ed Scherer

I believe so; the same relay part number (1H0.953.227 or 111.953.227) is specified for all 928 model years.

U-928

I appreciate it. Thanks a lot.