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Discussion Starter #1
Hey guys, I've had great luck using the Sylvania Zevo led bulbs you can get at local auto parts stores for around $25.

It uses different leds for the low and the high so you get great contrast, just like factory. It also fires backwards into the reflector so you get a nice even light distribution just like factory.

I installed them on my motorcycle and they are great. They come on super fast. But when I installed them on my T bird, the cruise control doesn't work. I swapped to an electronic flasher, but that doesn't have any effect as far as making the cruise control work again.

If I have one bulb incandescent and one led, the cruise works, but if both are led, it doesnt.

It's very strange.

Has anyone had this issue before?
 

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Hey guys, I've had great luck using the Sylvania Zevo led bulbs you can get at local auto parts stores for around $25.

It uses different leds for the low and the high so you get great contrast, just like factory. It also fires backwards into the reflector so you get a nice even light distribution just like factory.

I installed them on my motorcycle and they are great. They come on super fast. But when I installed them on my T bird, the cruise control doesn't work. I swapped to an electronic flasher, but that doesn't have any effect as far as making the cruise control work again.

If I have one bulb incandescent and one led, the cruise works, but if both are led, it doesnt.

It's very strange.

Has anyone had this issue before?
Yes, and it's for the same reason why the tail lights on most LEDs are lit up when the power is on (dimly!) ... the cruise control uses the incandescents to pull the input down, and there's not enough current on your Zevo's to do that. (On most LEDs, there's enough current flow; but there's also enough to start the LEDs to, well, emitting light.)

A load resistor will do that; you don't even have to go the 6 ohm route.

IIRC, about a 570 ohm 1 watt resistor on either side does the job just fine. And doesn't get anywhere near as hot (for bulletproof, use 570 ohm 5 watt sandohms and bolt them to the body somewhere ... )

(I need to do that to my Cougar to get the LEDs out when the power's on but the lights are off ... )

RwP
 

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Discussion Starter #4
Yeah, I definitely don't want to go with 6 ohm.

Do you know if it pulls current on the running light side or on the brake side?
 

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Well this thread has definitely made me decide to stick to incandescent taillight / turn signals. I did the interior all LED including the dash and the Reverse bulbs which all was a worthwhile improvement.

Using a load resistor has always been a such big negative . IMO the best reason to switch to LED is the lower power consumption.
 

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Discussion Starter #6
Well this thread has definitely made me decide to stick to incandescent taillight / turn signals. I did the interior all LED including the dash and the Reverse bulbs which all was a worthwhile improvement.

Using a load resistor has always been a such big negative . IMO the best reason to switch to LED is the lower power consumption.
Your not making sense. Did you read the above where you can run a 570 ohm resistor as opposed to a 6 ohm? It's barely any load at all.

I'm gonna experiment with some small loads on just one side and see what it takes to get it working. I might even just add a weak 1 or 2 watt tiny bulb to the wires. I don't know if it's the running wires or the brake wires that need a little load.

The led zevo bulbs are worth it. It's a bit brighter than stock on the brake circuit, plus the immediate on and off really grabs your attention. It should help people see your brakes and rear signal better.

Here's a video of my bike with led on left and incandescent on the right. Look at the speed difference when I apply the brake. The incandescent takes much longer to come to full brightness.

https://youtu.be/HXzbD58GihE
 

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Umm ... it's the brake lights.

See, it's the fact that they're connected to the cruise control electronics so that, with incandescents, it holds that line close to ground; when you step on the brake pedal, it goes to 12V or so and says "Whoa! No cruise!"

With the LEDs, there's not enough current to pull it down properly; all we need is to pull it down far enough, which doesn't take a full "load resistor" of 6 ohms.

RwP
 

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Discussion Starter #8
Umm ... it's the brake lights.

See, it's the fact that they're connected to the cruise control electronics so that, with incandescents, it holds that line close to ground; when you step on the brake pedal, it goes to 12V or so and says "Whoa! No cruise!"

With the LEDs, there's not enough current to pull it down properly; all we need is to pull it down far enough, which doesn't take a full "load resistor" of 6 ohms.

RwP
I think your wrong on this. My car has a seperate switch on the brake pedal for the cruise control. 2 switches total.
 

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Discussion Starter #10
That's the travel switch, cruise uses both inputs
So cruise control uses both switches, plus it monitors the load across the tail light bulbs? It seems a bit odd.

I think I have a 194 bulb and socket laying around. Maybe I'll try wiring it into the circuit and see what happens. Hopefully we need the small load on the brake/bright circuit so my little 194 bulb will only come on with the brakes. Seems simple enough.
 

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So cruise control uses both switches, plus it monitors the load across the tail light bulbs? It seems a bit odd.
Definition.

It doesn't MONITOR the load.

The lamps are the pull-down RESISTOR for the logic input. That way Ford could save the price of a 2 cent resistor, plus it means that with the brake lights out, the cruise won't work - which makes a small bit of sense for safety, I guess.

But check your EVTM sometimes; it's amazing what you find out when you peruse it.

In this case, it's Section 31; pages 31-1 and 31-2 shows that run. (Also, if you could stand the heat, incandescents in the CHMSL should do it; but dang it, THOSE need LED worse due to the heat! Whuddya gunna dew?)

RwP
 

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Discussion Starter #12
What do you mean by "logic input"? Is this the cruise control electronic box? My manuals don't go into details on the cruise control. It just says to take it to the dealer. Lol.

What is EVTM?

What is CHMSL?

You got me lost.
 

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What do you mean by "logic input"? Is this the cruise control electronic box? My manuals don't go into details on the cruise control. It just says to take it to the dealer. Lol.

What is EVTM?

What is CHMSL?

You got me lost.
Well, the input to the cruise control electronic box is either a logical "OFF" or a logical "ON" for the brake lights. And no, that's not in the manual; but since I've been tickling electrons since the 60s and work on computers for a living (at the repair level), I tend to think in the terms of a logic device.

The EVTM is the Electrical Vacuum Troubleshooting Manual; if you're working on your car's electrical without one, IMO, you're about like those apes at the start of 2001:A Space Odyssey and just beating on things with clubs and grunting *grins*

The Center High Mount Stop Light, or CHMSL, is that light up on the package tray in the back.

RwP
 

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Your not making sense. Did you read the above where you can run a 570 ohm resistor as opposed to a 6 ohm? It's barely any load at all.
Don't take what I said the wrong way, it is very much appreciated that you take the time to post this stuff!

I was speaking in general, most people put in LEDs and then slap in a big resistor with a heat sink and call it a day. That seems kind of a hack job to me. I have been thinking of doing LEDs and getting an electronic flasher. I will monitor this and if you have good results with a low resistance, I may even try it out.
 

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There are two switches on the brake pedal; on NO (normally open) one NC normally closed.

If either change, the system disengages.

The BOO switch goes to the brake lights; the special thing about the center brake light is that it doesn't go thru the MFS (Blinker switch).

I'm not sure anything else is on the other switch at all, thus the need for a load.

A 570 w resistor only needs to be 1W to be at a 2x safety factor; 5W s 10x. :)

These are 560 ohm, and have mounting flanges for $3.




This is a flame proof design, $0.64ea.



:)
 

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Don't take what I said the wrong way, it is very much appreciated that you take the time to post this stuff!

I was speaking in general, most people put in LEDs and then slap in a big resistor with a heat sink and call it a day. That seems kind of a hack job to me. I have been thinking of doing LEDs and getting an electronic flasher. I will monitor this and if you have good results with a low resistance, I may even try it out.
The electronic flasher only solves the hyperblink without the need for resistors, cruise will still be an issue.

Buying an electronic flasher isn't necessary btw. Cut this this trace my meter lead is on and hyper flash is disabled.

 

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Discussion Starter #17
I finally got it all working. I didn't want to order parts online, so I took a single 194 bulb and socket I had and used some splices to tap into the ground wire and brake wire (black and yellow wires).

Out of curiosity, adding the bulb to the running light wire had no effect, it's the brighter brake wire that you need a little load on. So now I have a little 194 light in the trunk that comes on with the brakes. No big deal. Lol

BTW, without that little extra load I noticed that the bright, brake led glowed a little when the running lights were on. With the 194 plugged in, it went out.

I also found out that the Zevo bulbs are polarity sensitive. I plugged in both and none were working. I freaked a little thinking I had fried them. Then I tried flipping them 180° and bam, all good again. :)
 

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Discussion Starter #19
I had them in and out a lot while I was testing and figuring things out. I think the first 8 plug-in were correct! What are the odds?

Then I get both backwards and think I broke them. Lol
 

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Discussion Starter #20
I did the same thing, somehow I managed to install both rear ZEVOs in the correct orientation on the first try, but installed both of the front ones backwards.
Why did you do the fronts? Did you just want that fast turn on/off?
 
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