Hazard Flashers Stop Flashing When Brake Is Applied - Flaw or Feature?

[cc333]

Lots of questions here....

So, I don't know if this is normal behavior, but when I have the hazards on, they stop flashing when I put my foot on the brake.

Is this by design, or some kind of problem caused by the aftermarket trailer brake controller I have (whose make/model I can't recall at the moment)?

c

 

[AK49BWL]

It's normal...unfortunately.

 

[df2x4]

X2, that's normal behavior on these trucks.

 

[cc333]

Hmm, OK.

What an odd feature?

c

 

[AK49BWL]

That's what happens when they decide to run literally everything lighting through the steering column. The reason it does what it does is because the brake lights are combined with the rear blinkers IN the column switching setup. Problem is, they didn't think to cut that brake line input off when switching to hazards, so when you hit the brakes, EVERYTHING is getting power off the brake switch, bypassing the flasher module(s) entirely.

 

[cc333]

Hmm, if I understand it correctly, that suggests the wiring could be modified such that the flashers bypass the brake light switch, yes?

That isn't something I plan to do on my truck, but I'm nevertheless curious.

c

 

[AK49BWL]

Hmmm.... Yeah I guess technically it could be done. I think you'd have to add a relay tho.

Or do like I did on my truck, separate the flashers/blinkers from the brakes entirely. I have my rear upper bulbs as my blinkers and the lowers as my brakes now...Then I have a separate set of relays at the rear to combine the blinkers and brakes for the trailer.

 

[1ton-o-fun]

It's actually a safety feature. For vehicles that have taillights poorly thought out like ours (WHY didn't they do what @AK49BWL did from the start?!). From behind, your flashers don't necessarily mean that you are stopped. It SHOULD let the morons behind you know that something's up and to be cautious. But brake lights mean you're slowing or coming to a stop, which is more important for the morons behind you to know for sure. Engineers finally figured out that BOTH of these features would be important to know at THE SAME TIME and separated the turn signal/flasher from the brake light in the taillight assemblies.
I've never understood why several vehicles (our trucks included) have huge taillight assemblies and only utilize a portion of them.
@AK49BWL has it done right. I just haven't ever taken the time to develop an electrical skill set. I can remove and replace the shi* out of anything, but haven't done anything electrical beyond plug/unplug connections, lol!

 

[cc333]

Hmm, OK. I think Europe had that figured out as far back as the 70s, because lots of imports from the 80s have proper dedicated rear flashers.

Oh, well, I guess I'll live with it for now. It's not like I need them all the time (I think something would be seriously wrong if I did )

c

 

[sewlow]

GM's has done this for many years.
Both my '69 Chevelle, my '70 Nova, all the Impalas (12) & every one of the many square body's did this very same thing.
I don't know about the other manufacturers.
Out of the 50+ vehicles I've owned, only two were non-GM.