i have a 1997 f-350 powerstroke dual wheel 4x4 flat bed that i had installed led bucket lights on. since then i have had problems with the transmission up shifting and down shifting after 45 50 MPH. Went to a local auto parts store and they said i need a flasher. i installed the flasher and it helped with the blinker flashing fast but the transmission still fluctuates. IF anyone has had the same problem or any knowledge about this i would appreciate the help.

 

Welcome to FTE! Just so I have this straight, you installed LED lights and now you have transmission problems?

 

yes i installed LED bucket lights that you would see on a dump body. Someone said it was because of the electronic transmissio.

 

Unless you messed up the wiring, the two really can't be related. The turn/brake lights are simple power wires, no signals are really sent on them.

I would actually start my suspensions with the throttle position sensor. I think on the diesels it's built into the gas pedal. TPS can tell the transmission how much power your applying and it will decide to wait to shift a little longer.

 

Thats not entirely true. While I would suspect that the problem might lie elesewhere and your problems are circumstancial, there is a possibility that the LED brake lights can cause issues. The computer thinks that your brake lights are burned out based upon the low current draw of the LEDs. Since I knows it cannot sense when you are applying the brakes, it may change its shift pattern. You should install resistors in your brake light circuits. You can do a quick search on it to find out how to do it and what kind of resistors you need. I am going to be doing this myself, as the LED lights can also interfere with cruise control operation.

 

Do the lights work correctly ?

Just for S&G, disconnect the lights and see if anything changes.

Or unplug one side at a time,see if you can isolate any thing that way.

Other than that .

 

You nailed it.

 

That's interesting. Does the PCM have a load sensitive circuit for the brake pedal switch? That seems like a lot of work for nothing if there isn't a way for it to display that a bulb is out. When the pedal goes down and the switch closes, then the wire has 12v. The 12v with almost no amperage should be able to tell the PCM the brake is pressed.

 

I would agree with this is a possibility as well. I have heard of it happening before.

 

Interesting, I might agree w/ this if the trans was acting up w/the brake pedal depressed.

I didn't think the pcm would monitor the brake light circuit during regular driving.

Then again, I've been wrong before.

Subscribed, and re-checking for resolution !

Keep us posted.

 

Crazy but i have found this problem before, i had worked on a honda civic that shifted funny and cruse control would not disengage, all due to led lamps being installed with out the resistor.

 

thanx for all your feed back i will try the resistor. Im adament to find out what the problem is because the LEDs look so good and will be good for plowing season. I Will let you guys know how i make out.

 

I don't know how the PCM can tell or why it makes such a difference, but it does. If you have a 3rd brake light on the cab and it burns out it can mess things up too.

 

We just had this issue on a service truck. The tsb states that with either led or a burned out bulb the pcm senses the circuit open and under 30% throttle the torque convertor will not lock up or may lock and unlock. The resistors are 6ohm and 50 watts. Hopefully this helps other people.