Turn Signals On My Thunderbird LT

[Sedona Digs]

I recently tried replacing the turn signal bulbs with LED bulbs, which were supposed to be plug-n-play. After installing the front two bulbs I tested them, and found that the turn signals no longer functioned. It was suggested that I need to install all four bulbs to get matching resistance. This did not fix the problem. I then replaced all four bulbs with the original bulbs. Turn signals still would not function. I then tested all the fuses and found them to all be OK. Then, for no apparent reason, the right rear bulb, as well as the console bulb started functioning properly, including the turn signal cancellation when signaling a right turn!!! Signaling a left turn was still not working. Could it be the ECU? Any ideas?
Thanks,

 

[Qship]

LEDs draw a lot less power/resistance than incandescent bulbs so it could be fooling the CANBUS
electrical system on your T'bird into thinking there is a fault. If you have put all the old bulbs back in, try disconnecting the negative lead on your battery for a minute and apply front or back brakes to draw any residual power from the ECU. Reconnect battery and check lights. Make sure all bulbs are good and have proper connection/contact as well.
I have heard that when doing this mod, you may need to install inline resistor to get the proper voltage through the LED bulbs to make them function.

 

[sikatri]

Nice information Qship!

 

[Sedona Digs]

LEDs draw a lot less power/resistance than incandescent bulbs so it could be fooling the CANBUS
electrical system on your T'bird into thinking there is a fault. If you have put all the old bulbs back in, try disconnecting the negative lead on your battery for a minute and apply front or back brakes to draw any residual power from the ECU. Reconnect battery and check lights. Make sure all bulbs are good and have proper connection/contact as well.
I have heard that when doing this mod, you may need to install inline resistor to get the proper voltage through the LED bulbs to make them function.

I relayed your suggestion to the Triumph dealer. He said they tried your procedure, but it was unsuccessful. Not sure if they did. They tell me that Triumph Support says the instrument cluster needs replacing. What do you think? How would installing two LED turn signal bulbs fry the instrument cluster? I would hate to purchase a new instrument cluster for over $500.00, and not get the issue resolved.
Thanks again!!
John

 

[Qship]

That is odd that it would cause a problem with the instument cluster. Was everything working fine in your cluster before you tried the bulb change?
They had to go to Triumph support to find this out? I hope they have the proper diagnostic tools to do the job. I know that the ECUs are locked on the T'bird LT and Commander models and can only be accessed with the Triumph software.

 

[Sedona Digs]

That is odd that it would cause a problem with the instument cluster. Was everything working fine in your cluster before you tried the bulb change?
They had to go to Triumph support to find this out? I hope they have the proper diagnostic tools to do the job. I know that the ECUs are locked on the T'bird LT and Commander models and can only be accessed with the Triumph software.

Everything was working fine with the instrument cluster prior to installing the LED turn signal bulbs. I did learn that the flasher relay module is part of the instrument cluster, so that is probably why Triumph is suggesting replacing the cluster. Before doing this, I have been advised by another triumph dealer to have the software re-installed, as it may have benn corrupted. Will let you know if this works. Thanks again!
John

 

[Kevs56]

Everything was working fine with the instrument cluster prior to installing the LED turn signal bulbs. I did learn that the flasher relay module is part of the instrument cluster, so that is probably why Triumph is suggesting replacing the cluster. Before doing this, I have been advised by another triumph dealer to have the software re-installed, as it may have benn corrupted. Will let you know if this works. Thanks again!
John

Hi John, just a quick question.
I have recently replaced all globes on my LT with leds, except for the indicators.
However they all seem to be working except for the indicators which are now not working at all.
Intried putting all the original globes back in but it made no difference and have also tried disconexting the battery as suggested to no avail.
Any further suggestions from your research would be much appreciated.
Thanks, Kevin

 

[atomsplitter]

Without looking at a schematic it's hard to diagnose the problem, it's all guess work. I would suspect the flasher relay is a potential source of the problem since it's looking to see a set amount of resistance when the unit is activated to set the desired flash rate. Hyper flashing is a typical problem when going from incandescent to LED due to the lower resistance of the LED and usually requires an inline resistor installed to tame the flash rate. With newer systems that have selectable flash rates the lower resistance can really upset the apple cart.