Intermittent - lights do not flash when unlocking

I noticed that intermittently my lights (front and rear) do not flash when unlocking the truck the first time I hit the button. If I hit the button a few times they work, and I have only noticed it while unlocking. Any ideas?

I have Morimoto XBs and the Hottails in the rear. Both sets are about a year and a half old. Its not the lights causing it obviously.

@memario1214 @RainMan_PNW

 

Tagging you @RainMan_PNW

 

does the truck actually unlock when you hit the button that first time (even if the lights don't flash)?

 

Yes it does.

 

Any aftermarket equipment installed that integrates or ties into the unlock/security? (Aftermarket security, remote start, etc.)

 

Not at all. It just started doing it about 2 weeks ago.

 

Still have no idea what is causing this. I even changed the FOB battery again.

 

Honestly - no real idea. I’m slammed right now at work and home, so no real time to go digging through the wiring diagrams to try to understand what might be controlling that flash. Though on a 2020 I’m pretty sure it’s the ECU and not some external relay.

 

@Jeff_5_7 any ideas?

 

Does the horn work? I think it honks or beeps when you lock or unlock. If this is all working and the truck is unlocking the fob battery is good.

Its an issue inside the truck with sending a signal to the lights, have to tried with the factory lights just to make sure?

I think its the blinkers that flash correct?

 

The horn only sounds during an alarm. I changed the Fob battery as well. I haven't tried the factory lights yet but it has been fine for the last couple of years. Yes, it is the front and rear turn signals that flash. Sometimes they don't flash when locking either. Every once in a while they will flash like the are supposed to on the the first try, but most of the time they won't until I press the button a couple of times.

 

Yea very strange, I though there was a beeper also that made a sound.

Have you looked around the Techstream customization menu? This sounds like something you can enable/disable.

 

It's an intermittent issue so it wouldn't be the on/off setting. There is a beeper type unit that will sound if you do something like lock the doors and one is not closed all the way. I'll check for that.

 

So I tried testing the warning buzzer. For normal operation, If you leave a door partially open and lock the truck with the fob, the warning buzzer would sound a steady tone. I tried that a few times today and it no longer does it. I'm at a complete loss between no buzzer and the lights not flashing when they are supposed to.

 

@Ruggybuggy any ideas? Thanks.

 

It's not turned off. All of a sudden I just started getting intermittent times to where they don't flash during unlocking. Now it's 98% of the time. The doors lock and unlock without any issues. If you partially close a.door and try to lock it with the fob, you would get a long tone letting you know that a door is open. It doesn't do that any more either.

 

What happens when the door is partially open and you hit the unlock?

 

It unlocks fine.

 

Do the lights flash and confirmation beep?

 

Also if you start the truck and walk away with the key does it long beep?

 

Ok i went out and tested it. If I leave a door partially open, all doors lock but no beep. When I unlock it, it beeps.

 

Just another thought. Do you have LED interior lights installed and/or LED cargo bed light installed? The LED lights can cause interference issues with the fob. The shark fin is the antenna for the fob and is susceptible to interference because of its proximity to the LED lights.

 

I have the interior leds from the factory and no I do not have the leds in the cargo lights. I was aware of that issue a while back. Everything worked fine since the truck was new. It started this a couple of months ago.

 

Have you tried the other fob?

 

Yes, and even tried new batteries in them.

 

Try disconnecting the battery for 10min and reconnect. Yes I'm grasping.

 

@Toytech6466 and ideas?

 

I would have to look at a wiring diagram, does it have a separate relay for the lights, do you have aftermarket lights? I have seen customers have issues where they park their car and there is a lot of interference that has cause issues(work at a radio station)?

Have you checked TSBs

 

Everything has worked completely fine for 3 years and then it started.