LED Tail Light Question

[jessemthompson]

I would like to put LED tail lights in my 72. I have an LS swap in my truck though. I have read that the LEDs will cause an issue with the torque converter lockup and that you have to put resisters in to use LEDs. I have never used inline resisters. Would anyone with experience please chime in to help me out. What size resister, how many, does it go on the ground side? Thank you in advance.

[Rufas]

I'm using the sequential rear turn signals from Brother's. I did have to install a solid state flasher and keep the front turn signal 1157 bulb. I kept the front bulb because I didn't want to use the load resistors. No problems with interfering with the trans. But then again I'm using a 700R.

[Andy4639]

I'm all LED's and 6.0 with 4L80E transmission with no problems that I know of.

[jessemthompson]

Originally Posted by Andy4639

I'm all LED's and 6.0 with 4L80E transmission with no problems that I know of.

Do you run a resister in-line anywhere Andy? Did you change to a solid state flasher?

[Andy4639]

Originally Posted by jessemthompson

Do you run a resister in-line anywhere Andy? Did you change to a solid state flasher?

I changed the emergency flasher and regular flasher both with these.

[demian5]

I put LEDs in the rear of mine with filaments everywhere else. Didn't change flasher or anything. It all works great.

[Andy4639]

Originally Posted by jessemthompson

I would like to put LED tail lights in my 72. I have an LS swap in my truck though. I have read that the LEDs will cause an issue with the torque converter lockup and that you have to put resisters in to use LEDs. I have never used inline resisters. Would anyone with experience please chime in to help me out. What size resister, how many, does it go on the ground side? Thank you in advance.

I have had my truck for about 5 years with all LED's and this is the first time I have ever herd of it being a problem for the transmission.

[demian5]

Originally Posted by Andy4639

I have had my truck for about 5 years with all LED's and this is the first time I have ever herd of it being a problem for the transmission.

Yeah that's some shifty information...

[jessemthompson]

I appreciate all the information. I was doing some reading a while back and someone had an issue with their torque converter lockup on their 4L60E. After some troubleshooting they found the problem to be not having enough resistance in the brake light harness because of their LED tail lights. Thank you for everyone’s input.

[MfBox]

Originally Posted by demian5

Yeah that's some shifty information...

[Problems]

I know all LEDs is a problem with the late 90’s cruise control modules unless you wire in a relay. I can’t imagine why it would be a problem with torque converter lock-up. Unless you are using some aftermarket lock up controller that finds ground through the brake light circuit.

[jessemthompson]

Originally Posted by Problems

I know all LEDs is a problem with the late 90’s cruise control modules unless you wire in a relay. I can’t imagine why it would be a problem with torque converter lock-up. Unless you are using some aftermarket lock up controller that finds ground through the brake light circuit.

The torque converter lockup on the harness wires into the brake light switch on my LS Harness

[darrellyates]

I didn't have any trouble with my LED tail lights and the 4L60E I had until I added the cruise control. Then, the cruise didn't work and I had to add a resistor to the ground side, I believe it was. I've been told a light under the dash works too, but I just used a resistor.

No issues on the new truck, running LED's everywhere. The cruise control is, however, the new plug and play from Dakota Digital and just piggy backs on the electric throttle.

I haven't had any issues (yet).

[bbrriiaann1973]

I have a 383/700R4 with rear LED lights and I have had zero issues with it

[87Skier]

Originally Posted by jessemthompson

I appreciate all the information. I was doing some reading a while back and someone had an issue with their torque converter lockup on their 4L60E. After some troubleshooting they found the problem to be not having enough resistance in the brake light harness because of their LED tail lights. Thank you for everyone’s input.

I could see that being an issue. I have heard mixed information when it comes to positive apply vs. negative apply for the brake circuit and LS swaps.

If you are going to use LED tail-lamps, use the digital flashers someone posted above. If you have trouble with the turn signals flashing too fast or not at all, add a load resistor. If your having trouble with the torque converter after all this and you have verified it in a scanner, then add a relay with pull-up/pull-down resistors depending on your situation.

[Robznob11]

Originally Posted by jessemthompson

The torque converter lockup on the harness wires into the brake light switch on my LS Harness

The TCC switch is 12v on all the time and the brake switch opens the circuit. There is a separate circuit that is normally open and makes the connection for brake light function. There should be no interference since they are completely separate circuits. Now with that said if you have a swap using the cruise option...depending on how you have it wired you may need a resistor to make the cruise work. I have seen this before on 2 different swaps. There are always ways around these problems with relays. I have a wilwood MC with pressure brake switch. I have full LEDS and I trigger a relay to open for TCC , off of the brake light circuit with no issues.

[Robznob11]

Originally Posted by 87Skier

I could see that being an issue. I have heard mixed information when it comes to positive apply vs. negative apply for the brake circuit and LS swaps.

If you are going to use LED tail-lamps, use the digital flashers someone posted above. If you have trouble with the turn signals flashing too fast or not at all, add a load resistor. If your having trouble with the torque converter after all this and you have verified it in a scanner, then add a relay with pull-up/pull-down resistors depending on your situation.

Many times if you add a LED flasher and it does not blink it is because the led flashers are polarity sensitive and the wires need to be unpinned and reversed. You can also buy adapters to reverse polarity on a stock style fuse box. Many times people can't figure out why they flash on hazzard but not on turn, this is usually the reason. The hazard side will work because the way they are hooked up has more load...I suspect that current somehow backfeeds and finds ground. But the turn is separated and has no way for the extra load or backfeed. Also since gm did not have flashers that were polarity specific they did not care which side was hot or ground. So its possible for the turn to be opposite of the hazard on the harness.

[phat69]

Use the brake light switch circut to control a relay for the TCC and brake lights.