cruise not working

Discussion in 'Chevy Tahoe Forum (GMC Yukon, Cadillac Escalade)' started by CG-ITS, Aug 28, 2009.

  1. CG-ITS

    CG-ITS New Member

    hey guys,

    sorry to bug you again, but I need some input with this one:
    So today I finally got to install my new LED taillights, everything works, lights, brakes, turn signals. perfect.

    But now I can't get my cruise control to work anymore?? I don't know if that's related in any ways???

    I looked through all the fuses (drivers side dash pannel and the one under the hood) but they are all fine, especially the 10A one that says "cruise"...

    So what happens is when I press the set button nothing happens. Everything else works on that switch, turn signals, windshield wipers, washers....

    The funny thing:
    When I have either turn signal on and then take the foot of the gas and then press the set button cruise will eventually come on for just a split second, just long enough to notice the light come on and to notice that cruise is taking over the vehicle, but then immediately the light goes out and you're back to pedalling...

    I looked at the brake lighs, they go off as you lift your foot off the brake pedal, so I don't think that that's it...

    Does anyone have an idea what could be causing this???

  2. CG-ITS

    CG-ITS New Member

    stay away from led lights

    gee, I can't believe it.

    I just wanted to be sure, so I put my old taillights back in and look at that: now cruise is working again!

    Does make me wonder what the Tahoe's computers monitor that would make it shut off cruise control when switching to LED?
    Does it monitor amperage draw? Or voltage drop? Or Resistance?

    I have a fluke 1587 Insulation here with me so I could test a few things, I just don't know if I'm willing to put any effort into this to then find out I can't do anything about it without at least voiding the warranty on the lights...

    Does anyone here have aftermarket lights on their Tahoe?

    I see aftermarket lights on the older models quite a bit, but so far I've only seen one 2001 with LED Taillights....
  3. kandave

    kandave New Member

    Hi, did you get any further with your problem? I have discovered a similar isue after fitting LED rear lamps to the rear of my RV (2000 Chevy Express chassis).

    I found the following bit of of info elsewhere which seems to confirm that the cruise control is linked to the vehicle lighting system:

    The NTSB(National Transportation Safety Board)doesnt reccomend using Cruise Control on any motor vehicle when driving in low light conditions, so Chevrolet designed most Cruise Control units to turn off when you turn your headlights on. To prove this for yourself, turn your Cruise Control on during the daytime, make sure Cruise is working andthen turn on your headlights. Your Cruise Control will immediately diengage. Now turn your headlights off and restart your Cruise Control. Your Cruise Control should work properly.If your vehicle is equipped with DRL(Daylight Running Lights), These lights will not affect your Cruise Control.My '98 Chevy Express Van works the same way. You can also verify this through your local Chevy dealer.

    Converting it back to non-LED is going to be a lot of work so I'm keen to find a solution that allows me to bypass whatever it is that knocks the cruis control out of action.

    Any solutions out there?

    PS I'm UK based and so can't just go down to my local Chevy dealer!
  4. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    The cc is looking for a resistance range in the brake light circuit. The led's are not drawing enough current so the cc cuts out. I would contact the distributor for a fix. They probably have a resistor or relay that you can wire in the circuit.
  5. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    Voltage readings after swapping to LED's has been a problem in other make of vehicles.
    Many vehicles end up with faster flashing turn signals after swapping to LED's for the signal lights.

    The fix is to place a resistor in-line to duplicate the required voltage.
    You'll need to find the reading the system's looking for then go to the nearest Radio Shack and find a matching resistor to solder in line.
  6. kandave

    kandave New Member

    Hi, many thanks to unplugged and tbplus10 for your suggestions. I contacted the manufacturer who came back with some possible solutions along the lines already suggested. I have shared their info below as Trucklite is an American manufacturer. Hope it helps others.


    The first thing is to check with the MANUFACTURER of the vehicle and find out what components may be affected by using the LED stop/turn lamps. As an example certain electronically operated systems, such as cruise controls or ABS systems may respond improperly to the difference in resistance to ground that results when LED’s are substituted for incandescent lighting devices.
    1. The original flasher is not designed to operate with the LOW current draw of
    LED lamps. If possible replace the flasher (if a 2 prong) with Truck-Lite ULTRA-FLASH II (part numbers 97231, 97232) or HEAVY DUTY FLASHER (part numbers 97270, 97271). Or Signal Stat part numbers 270, 285 (if a 2 prong) or 275 (if a 3 prong). These flashers are designed to work with LED and/or incandescent lamps.
    2. Add one resistor in parallel with each LED lamp. One side of resistor is attached to the negative (ground) wire and the other side of the resistor is attached to the positive (hot) wire of the turn signal function. Use a RH-25 aluminum housed wire wound resistor (25 watt/10 ohm) or equivalent.

    CAUTION: Do not mount resistors to painted, plastic or wood surfaces as the resistors will get HOT! Once the resistors have been installed do not touch without protective gloves on as you may suffer burns.
    Possible sources for the RH-25 resistor:
    Allied Electronics, (800) 433-5700,
    # 296-1090, 25 watt, 10 ohm
    # 296-1140, 50 watt, 10 ohm
    # 796-8109, Thermal Compound, 1 oz tube
    Newark In One, (800) 463-9275,
    # 91F5377, 25 watt, 10 ohm
    # 91F5397, 50 watt, 10 ohm
    # 00Z1880, Thermal Compound, 5 oz tube
    NOTE: Before mounting the resistors it would be a good idea to add some thermal compound to the back of the resistors to help transfer heat.
    3. Try adding a marker lamp (with a 194 or 168 bulb) to the turn signal function on (both sides); to see if that would help. If not you may have to use a stop/turn lamp (with an 1156 bulb).
    4. If none of the above works you’ll need to go back to the incandescent lamps.

    Technical Support
    Phone: 888-562-5012
    Fax: 716-661-1287
  7. virtualryan

    virtualryan New Member

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