Ford Mustang Forum banner
1 - 7 of 7 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
I just installed LED bulbs in my 2007 Shelby GT And they blink really fast and the inner lamp on each sight do not flash or illuminate when braking.

Do I need a resistor to make all work properly? If so, what would the Ohm rating be, how many and where would I install?

Thanks in advance,
 

·
Registered
2002 Mustang GT coupe
Joined
·
119 Posts
If you have a replaceable flasher relay, you should replace it with a modified electronic relay specifically for LEDs and specifically for your car. That is the best/cheapest option. If there is no replaceable relay, replacing all the LEDs, both front and rear, with CANBUS ready LEDs (Lasfit T-series, etc) should fix you up. Those are more expensive than the standard $20 LEDs. Installing load resistors should be your last resort because most of them require cutting and splicing/soldering the resistors into place and you have to find a suitable place to mount them onto a metallic surface. There are resistor kits that don't require cutting and splicing but you still have to mount the resistors to a metal part of the car body. Amazon, LMR, American Muscle and others will have what you need.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #3 ·
If you have a replaceable flasher relay, you should replace it with a modified electronic relay specifically for LEDs and specifically for your car. That is the best/cheapest option. If there is no replaceable relay, replacing all the LEDs, both front and rear, with CANBUS ready LEDs (Lasfit T-series, etc) should fix you up. Those are more expensive than the standard $20 LEDs. Installing load resistors should be your last resort because most of them require cutting and splicing/soldering the resistors into place and you have to find a suitable place to mount them onto a metallic surface. There are resistor kits that don't require cutting and splicing but you still have to mount the resistors to a metal part of the car body. Amazon, LMR, American Muscle and others will have what you need.
Thank you for the reply. I will check for the relay. I think I have one…
 

·
Registered
2002 Mustang GT coupe
Joined
·
119 Posts
One other thing I noticed about the LED tail lights is that non-CANBUS LEDs disable the cruise control feature. I don't know if that's an issue with your model year but mine is a 2002. And, after replacing the LEDs with the CANBUS LEDs, the cruise control started functioning again. But I accidentally activated the turn signal and it disengaged the cruise control. That's not good for changing lanes. o_O I think installing the CANBUS LEDs in the front turn signals might fix that problem. The rear lights are already CANBUS types. I'll let you know.
 

·
Registered
Joined
·
519 Posts
I put in a sequential light kit and put in LED's. There is a bit to learn about LED compared to regular bulbs especially the dual element type bulbs as my back lights are. \
1st - they are polarity sensitive (at least the ones I got were). Put them in backwards, and they don't work.
2nd - you can get back feeding because rather than use 2 separate elements of LED's, the bulbs (I used) had a voltage dropping resistor feeding a common set of LED's. When the brake/turn signals are activated, through one terminal, the resistor is bypassed and full voltage goes to the LED and they are bright. Turn on driving lights, and the 12 vdc goes through that resistor and drops the voltage which causes the same LED's to be on but not so bright. This causes feedback between the 2 signal lines, To get these to work, I had to install a diodes so that when the brakes come on, the voltage doesn't go back up the driving light circuit. Works fine now. This could be your issue.
 
1 - 7 of 7 Posts
Top