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SOLVED - Cruise Control and All LED brake light conversion - thanks Tore!
A little over a year ago I converted the last of my brake lights, the CHMSL, to an LED strip. I took my my CHMSL strip and soldered a bunch of little LEDs to it.
The basic problem is that if you have converted all your brake lights to LEDs, you will find that your cruise control is inoperative unless you present a resistive load that simulates a halogen brake light filament when not applying the brakes. The cc computer looks for a tiny current through this filament to ensure the brake lights are operational before allowing the cc to activate.
One way around this is to wire a power resistor in parallel with all the brake lights. This power resistor would simulate the resistive load of a halogen lamp --- and also generate tons of heat when the brake pedal is applied. I did not effect this workaround because I thought it was an inelegant brute force way of solving the problem.
The elegant way to solve this problem is to use an automatic mechanical switch. That switch would automatically present the resistive load when the brake pedal is NOT applied. This resistor could then be very light duty (and not create a lot of heat) because it's purpose would be to sink the tiny bit of current that the cc computer looks for when the brake pedal is NOT applied. The switch would then automatically take the resistive load OUT of the circuit when the brake pedal IS applied ---- so as not to burn up the resistor.
I planned to fashion this circuit last January, but life got in the way. Imagine my surprise when our very own gracious Tore Bergvill decided to productize this concept. Tore graciously let me try his prototype "Smart Ballast" solution for LED brake lights for the 993. It works like a charm! I used weatherproof automotive grade connectors to connect the ballast with my car's wiring --- which I cut, soldered, heat-shrink-tubed, and then F-4-Self-Vulcanizing taped. Thanks Tore!
^ Good timing, I had not installed the LED strip yet so now I can proceed and order this from Tore together with the Continental TR7412UB-OR Radio Deck.
Thanks Tore!
I can drive east for 16 hours at highway speed and basically never have to turn the steering wheel. It is not fun holding the throttle at steady speed with your foot for that long. Cramps.
Even 16 hours driving just straight (sounds like my first 993 trip from Ohio to MA), I'd prefer to throttle and gear up and down a bit and stay connected (also better for the engine and transmission, or so I'm told). But that's why I drive a 993. It's reconnected me to my love of driving, and it's a thrill every time I get behind the wheel! But to each his own, and no disrespect. Cheers!
No worries. I feel the same way when I drive west into the mountains, and don't use snooze control when going that way. But prairies are a chore, no doubt about it. Plus cruise keeps my foot from creeping down into the "faster, faster" zone where it changes from just a ticket to mandatory court appearance and license suspension.
Glad for all those who wanted this fix, but cruise control why?
Because I like all the systems in the car to be operational. It is similar to the airbag system. I've religiously avoided activating the airbag system .... but I like knowing that the system is operational should I ever decide one day that it needs to be used.
Because I like all the systems in the car to be operational. It is similar to the airbag system. I've religiously avoided activating the airbag system .... but I like knowing that the system is operational should I ever decide one day that it needs to be used.
Agreed. That's precisely what has me thinking about installing it in both of my cars. Particularly since I haven't yet installed the third brake lights. But the airbag is perhaps not the best analogy as this is a safety device I would not live without (pun intended). To the contrary, I'm not sure any safety is gained by utilizing the cruise control. Nevertheless l do want the system available in case the next owner wants it.
I've had a prototype "Smart Ballast" from Tore installed in my 993 for about a month now, and can confirm Jlaa's experience. My installation was not as elegant as his, just two Scotchlok taps, but it does the job. The cruise control now works perfectly, along with the full LED complement including CHMSL.
Very cool that there is a solution to this problem. I've been holding out on the LED thing. Thanks a lot, Rennlist and Tore - more projects to add to the list!
And for the record: I love cruise control and use it all the time. I love seeing an officer with a radar gun out and just cruising right by, stress free, because I know I set the cruise just slow enough to avoid a ticket.
I also like a radio, A/C, heat, power windows/locks/steering/brakes, turn signals that flash and cancel by themselves, synchromesh grearboxes, electronic starting and other convenience features. I could definitely do without the immobilizer and keyless entry though.
Led Strip Lights - led light strip is a generic term used to describe the many different types of led lights that come in strips. depending on how you plan on using the leds, you may actually need one type of led light strip. Then water proof self adhesive led light in blue color with output driver.
02-13-2016, 12:21 PM
SOLVED - Cruise Control and All LED brake light conversion - thanks Tore!
