ok heres the problem. I have changed my tails, and 3rd brake light to leds. I had load resistors, but had problems with heat and corrsion. So i ditched the load resistors, and installed a electronic flasher. Now my cruise wont work. Any ideas/help would be great.

 

The cruise being inoperative is related only to the high-mount stop lamp. The flasher is a different issue.

Either 1) Reinstall the bulb for the high-mount stop lamp or 2) install a resistor in parallel with the LED to provide a "pull-down" of the circuit when the circuit is not active.

Reason:

The PCM monitors the voltage level of the stop lamp circuit (BOO) so that it can sense when the brake pedal is applied to disconnect or disable the Speed control.

In normal configuration, the incandescent bulb serves as a low resistance path to ground and "pulls" the circuit to ground potential when the pedal is not depressed. The PCM expects to see this zero voltage level whenever the brake pedal is not depressed.

The LED does not provide this low resistance path to ground to "pull" the voltage down when it is off. Consequently, the input to the PCM is floating, which its input circuitry interprets as the brake lamp is not off. It therefore disables the speed control.

The fix, other than re-installing the incandescent lamp, is to install a resistor in parallel with the LED to ground . A value of 2.2K 1/4 watt would likely be my first try. The resistor doesn't need to dissipate much power or sink much current, it just needs to pull the PCM input down to ground potential when the bake lights are not on.

Looking at the speed control and stop lamp schematics from 97-08, it looks like this would be an issue only on 05 and newer models. The older trucks used different mechanisms for signaling that should not be affected by an LED high-mount stop lamp.

 

BUMP...So has anyone installed a resistor ?..I did led tail bulbs front signals with a led relay..Thats working fine...Did the 3rd brake light led..lost my CC...Just looking for some experience with resistor installs...

Thank you

 

i've only done LED's on the rear of the truck. each side has it's own load resistor. after installing a LED third brake light with no resistor i ran into the same problem. (didn't think i needed it, i was wrong). i installed a load resistor on the third brake light as well, the cruise works perfectly now. i have not installed a LED relay at all, only load resistors.

 

What load resistors? Size etc...

 

The place you got the bulbs from might have some specific ones, but a quick google search shows the majority are 6 ohm 50 W resistors.

I don't know why both are offered, but they come aluminum & ceramic housing

Here is an example of one :
http://www.ultimateautoaccessories.c...source=Froogle

This is a quick diagram I found with google images on the install


Not sure if installing 1 for the CHMSL would do the trick or not, might need to install them on the S/T/T bulbs as well ( which you might need to change the flasher back again ).

This is only info I have found doing a google search, I don't have LED S/T/T bulbs installed, so I cannot say if any of this is accurate. Maybe the appearance forum might have some specifics ?

 

The above load resistors are for making the turn signals work properly, not allowing the the cruise to operate.

Different application and definitely NOT interchangeable.

 

Interesting...I would have assumed more people have had this problem and solved it..Guess it's back to a regular bulb for now.

 

The CC is not working due to the truck thinking the brake lamps are out.

If you have 2 LED S/T/T lamps and a standard bulb in the CHMSL, the CC will work. Adding the 3rd LED reduces the load enough.
Adding a load resistor to the CHMSL LED bulb might make the load look like the brake lamps are working again.

Same thing as installing all 3 as LED, and installing load resistors in the tail lamps.

Load resistors are generally associated with the fast flash symptom, and when installed in the S/T/T location ( with the CHMSL LED ) the load is enough to allow the CC to work.

This is a problem specific to the 04+ MY trucks where the CC is operated by the throttle motor, and the only other disconnect method is the CC disable switch on the brake pedal lever.

I seem to recall a thread where Recon ( not 100% sure on the mfgr ) had this as the solution for the CC disable after installing the CHMSL LED unit they sell.