Ok. My Electrical Gremlins are back….

Several years ago, all of my lights on my 99 Coupe started to hyper flash when I started the car. If I turned my headlights on, the flashing would stop but my left turn signal indicator would stay on.

My front market/turn signals & tail lights are LED.

I replaced my hyper flash harness and the problem was solved - At least it Was !!

Last weekend, the Hyperflash was back with the exact same symptoms.

Today, I replaced the hylerflash harness (again) which solved the problem - or so I thought.

I drove around the neighborhood with no issues. Then I parked the car so I could give it a good cleaning.

When I started the car, the hyperflash is back. Once again, turning my headlights on will cause it to stop but will keep the left turn indicator illuminated

The only code I have is for the BCM. It’s B2583

From what I can find, the code is for: LEFT FRONT TURN SIGNAL MONITOR CIRCUIT

Any Help/Guidance is Greatly Appreciated !!!!

Thanks in advance…

UPDATE - It’s not doing it every single time I start it. Did it 3-4 times in a row. Then I drove it with the parking lights on to keep the hyperflash from happening. I turned the lights off after a few minutes & the hyper flash didn’t happen. Parked the car & restarted it - the Hyper Flash was back.
then I started & restarted the can numerous times with 50/50 results.

~ I have already replaced the ignition switch.

 

So my guess is that if you removed the LED lights and the hyperflash harness, everything will work as designed? If so, you do not have a computer problem (mercifully) and your B2583 leads me to believe you are having intermittent contact issues. So, remove the bulbs and make sure they are seated correctly; our cars were not designed for LED and while most members have had success, you re car might need a little more attention beyond plug and play.

The fact that replacing components buys you a bit of time also tells me you may have a relay or wiring problem. If it is a relay, swap it. If you have a wiring issue (a faulty wire can miss read electrical current) you either live with it or switch back.

 

Moved to C5 Tech.

 

@Daypoblue

Did you ever rectify the problem?

I just installed Vette Lights tails and front markers and am having all sorts of weird electrical issues: horn honks, TC on/off/on/off, door ajar messages come and go, weird stuff.

 

Well, I hope you did work out your issue. It turns out mine is the BCM, the AC seems to be plugged up and condensation is dripping down to the BCM. Just so happened it coincided with installed the LED lights...