Newer vehicles STT error fix

[Steve0625]

When tapping into or adding STT lights to many newer vehicles the "lamp out" fast flash or warnings occur. The way around this is to use the trailer light tie ins. This solution should work for any vehicle that has the trailer tow wiring in place. Ford seems to include it in all of their light trucks, and Chevy/GMC may, as well. Dodge too for that matter.


S/T/T/R in the trailer tow wiring are all controlled by fused relays that are turned on and off by the CANBUS or PCM. Essentially, they don't care about too little or too much current draw in the way that the computers do for the normal S/T/T/R. The PCM or CANBUS senses the difference from what is expected and signals a fault of some kind, especially the dreaded fast flash/bulb out when it sees an LED in place of the expected incandescent. The trailer tow wiring works the way that everything used to do.


Taken from http://elightbars.org/forums/f13/fast-blinker-but-bulbs-still-there-49677/#post388138

 

[HILO]

If your adding extra stop or turn lights, yes, that will work. For CAN BUS system, it will not work for replacing OE halogen lights with LED, or even reducing the number of bulbs in a line. For example, I had to re-mount service bodies from 1998 Chevrolet 1500's with single STT to 2011 1500's, using the body STT lights that were the 'Jeep' style. There was no way to add a second set of STT lights that my customer would approve. Nor is there a turn signal flasher. I had to send all the new trucks to the dealer for a BCN flash. The dealer had to contact GM for each truck, provide VIN number, and then GM would send a password with a corrected turn signal flash. The password was VIN specific, and it cost $80.00 per truck.