Hey guys,
I recently started building a new bed for my 2007 5.9L dually.
I replaced all the clearance lamps, and brake and tail lamps with LEDs. (ones on the bed).
Everything seems ok when the headlights are off, but when I have them on, the lamp out chimes go nuts, and the turnsignals start flashing fast. it chimes when I hit the brakes, or use the turn signals, and right when I turn the lights on.
(but no brake light chime or turn signal fast and chime when the healights are off, wierd).

I have tried making sure i have at least one bulb on every connector, and making sure the ground configurations match stock(ground wire direct to bulb rather than from chassis).

Not sure what the heck I am missing here.....
Is it all about the lower current draw from the LEDs?
Or might I have some other config problems? like are the brake and tail tied together at all stock with a diode? or the grounds need to be independent from the chassis.

I experimented with putting an LED load on every single connector I had un done, and nothing is fixing the problem.

Has anybody fixed this kind of thing yet?
can i just reconfigure the computer to ignore this?
This has to be a common problem with utility beds, but I have not been successful with any searches.

Thanks!
Chris,

 

My guess is that the low current draw of the LEDS is fooling the computer into thinking that there is a lamp out. You will probably need a small resistor at each location to once again fool the computer into thinking that there is a good bulb there. This is easy to do. Figure out (measure) the current draw of the OE lamp at each location, calculate the equivalent resistance and then install the value of resistor from the line to ground, or across the terminals.
Bear in mind that with this configuration that the lamp out feature will no longer warn you if you do lose a lamp.

 

Stan, I think your fix may not work. You cannot put the resistance in series with the bulb as it will reduce further the current draw - - it will restrict the bulb from normal brightness - - you will drop voltage across the resistor reducing the voltage available for the LED and actually reduce the current. The parallel resistance could work but you have somewhat eliminated one of the reasons for the LED - - lower current draw. You will also need to determine the wattage requirement for that resistor for it will possibly be getting warm.
Bob

 

Bob, you are correct that a series resistor will not work. Go back and read what I wrote and you will see that I said to go from line (B+) to ground or across the terminals. That configuration is NOT in series. A resistor in series with LEDS will not only provide less lighting, but will probably still result in chimes and a lamp out signal.
I will admit that I forgot to mention that it is necessary to figure out the resister wattage.
As for the resistor defeating the purpose of the LEDS, maybe that is a moot point on a vehicle?

 

Ah, now I read what you meant. I was reading it different. Could be a moot point about the purpose, but the proper resistor could make the difference.
How well I remember that chime - - drove me nuts.

 

Hey guys,
Yes, I would assume that a resistor in parallel with with the LEDs will add enough total circuit resistance to make the computer happy.

Part of the point of LEDs is to reduce power draw to leave more energy available for other things.

Is anyone aware of how many individual circuits the computer is monitoring?
Like all the tail lights as one? or more than one discrete circuit?
I think the fuse box lists right and left tail light circuits.

Is anyone aware of a fix other than adding resistance? ( I would more likely just add more lights if i take the resistance approach)

Has anyone heard of a computer re-program? or know what guys with service bodies are doing?

This is another great example of where detroit has out smarted themselves. Their "feature" is WAY more of a pain in the *** than its worth. Kinda like this Takata airbag recall.... in the next 30 years, you are going to see A LOT more airbags exploding unexpectedly. Just look at any model T that has been sitting in the forest for 40 years. Everything rusts eventually.

Thanks,

 

Rather than trying to reduce the load on individual circuits, why not just add new circuits and bypass that stupid computer? Take a look at the Painless wiring from Genos. I have their 7 circuit auxiliary weather resistant fuse block on mine and it works great. Very easy to add circuits and not confuse the computer. Have it mounted behind the RH battery from the cowl and it looks very neat with only one wire going to the battery.

 

Mexstan,
I originally ran all of my lights off of the trailer wiring so that I would not have to cut the factory harness anywhere.
Problem is if you DONT have a load on the circuits the computer is monitoring, it throws a chime, and fast blink on the turn signals. And I cant unplug the computer all together, as it runs the rest of the vehicle.

 

OK I did my flatbed in all LED's this is what you have to do:

1) Tails / turns / back ups have to be tied into their respective factory harness (no universal ground).

2) you want a min of 2 and max 4 amps on each r / l circuit (tail / turn / back up light.) Go to your light mfr and determine their amp draw then do your math you can split the headache / side lights to help with this.

3) This is the load resisters I used (wired parallel in each r / l circuit turn/tail/b-u):

https://www.superbrightleds.com/sear...oducts/rl-650/

4) I had enough tail / clearance lights split between the r / l tail light circuits to achieve my min 2 amps.

5) if you don't want to hack the harness get the plug / harness out of a salvage yard that goes behind the factory plug at the bumper and tie into it.

6) Keep your trailer circuits separate from you truck circuits. I highly recommend you install a modulite on the trailer light side to protect your TIPS. Its $1,000 cheaper than a new TIPS

etrailer.com - Products modulite

Here is the truck I did:

https://www.dieseltruckresource.com/...-213006/page2/

Search for "RL-650" on the forum as we have discussed this before several times.

https://www.dieseltruckresource.com/...ng-ddtrdia.jpg