carlskisWP

Has anyone had success using red LEDs to replace the brake/running light bulbs on a 964? I bought a pair off of EBay a couple of months ago - 30watt 1157 Cree LEDs, the ones with two base contacts. They fit fine and lit up nicely as running lights.The problem was when I activated the brakes with the running lights on the bulbs actually got dimmer (or certainly didn't get any brighter). I see Tore B now sells LED bulbs for 964/993s, so I assume LEDs can work as brake/running lights - if you get the right bulb. BTW, I did also replace the 3rd brake light with a LED 1156 bulb and it works fine - brighter than the incandescent bulb.

-nick

There are a number of sources for bulbs, all different quality. I definitely would not trust ebay. Go to Tore, or try superbrightleds.com. There are a few threads here with info. Mine are from superbright and the parking/brake output is very obviously different.

911Jetta

For a start, check out what Vandit and Twood have come up with:
https://rennlist.com/forums/964-foru...ulbs-list.html

Derek911

I just converted to all led's in the rear. You will need the load resistors for the turn signals. (2- One for each turn signal)
Very happy with mine. I just looked at them again last night and was impressed. My tail lens is slightly smoked and the lights are still bright and clear.

With led's you must use bulbs the same color as the lens.

Just follow superbrights websites suggestions. Put in your car info and they tell you what you need for every light in the car. They recommend two different bulbs and warns that one may be too big, I got the bulbs with no warnings and they all fit fine.

Since I switched to led I also installed a brake light flasher in the third brake light which pulses the brake light for extra warning. The flasher only works with led bulbs since they are instant on/off. (60 watt fast flash option)

https://www.superbrightleds.com/vehi...=319&year=1991

-nick

Instead of a load resistor, replace your turn signal flasher relay with # CF13 GL-02. They're about $10. No sense in fooling around with a resistor.

Derek911

I'm running Incandescent Stealth Bulbs in the front, which look great with clear lenses, and led's in the rear. I didn't realize I could use the relay for mixed bulbs.
Superbright sells both the relays and resistors. The relay is the easier choice but there is plenty of room in the taillights for the resistors.

carlskisWP

Thanks guys. I will order some two intensity bulbs from Superbright or Tore B. I see that Tore has an LED package for a 964 with the flasher relay. Tore's relay is a CF14 though not CF13. My advise to anyone thinking of replacing the brake/running bulbs, don't waste your $10 or $15 on a cheapie Ebay "two" intensity bulbs (even though it's sold as a 1157). It most likely won't work correctly. The single intensity EBay bulb (1156) did work fine though in the 3rd brake light.

ToreB

Thanks for the references guys.

CF13 relay is not correct. It must be CF14.

The Porsche 964 and 993 needs brake light bulbs that are compatible with the brake light circuit construction in these cars. I have seen several cases of flickering light when using LED bulbs.

Cars equipped with a cruise control module will also need special attention when using LED bulbs as brake lights. This is only a problem when using only LED's as brake lights. Keeping one incandescent bulb such as the third brake light will avoid the problem. However, I have made a device called the Smart Ballast to cover this, allowing for use of LED's in all brake lights.

I do not recommend load resistors, either on the brake lights or turn signals. Such resistors are a waste of energy, bulky and get scalding hot in use. If used, they must be mounted on a proper heat sink.
Cheers,
Tore

-nick

CF13 GL-02 has the same pins and specs as the CF14 JL-02. I have no idea what is different, but the CF13 GL-02 is working for me

Derek911

Load resistors only become a problem on cars with tail lights that double as turn signals. In those situations, current would flow through the load resistor continuously when the light is on. But on 964's with dedicated turn signal bulbs, the resistors only have current through them when the turn signals or hazzards are on, which isn't much time to be concerned about heat. Tail lights can be on for hours during a drive, but turn signals only minutes at a time, even then at a 50/50 duty cycle.