LED Turn Signal “hyper flashing” 2011 Jeep

[LSU]

2011 Jeep Grand Cherokee.

Replaced the brake/signal lights With LEDs.

when signaling a turn the lights “hyperflash” with the engine running. With just ignition on but engine not running - no hyper flash?

1. Any idea why the lights hyper flash with engine running? But don’t hyper flash when just the ignition is on?

—-

2. Is changing the signal/flasher relay the solotion? If yes - suggestions/hints.

this is on my daughter‘s car, I’m visiting and my tools are 900 miles away.

I’m not much of a 12v electrician so amy tips or tricks are welcome.

thanks.

 

[tak1313]

I don't know about a 2011 Jeep specifically, but most modern cars don't use relays for the flasher anymore. They're just controlled by the BCM module. In fact, in most cars, the "tick, tick" sound is artificial because manufacturers found that consumers found it too weird to not hear the sound, formerly caused by the relay, with the flasher.

It may have to do with the LED driver on the bulb. LED bulbs sold to replace standard bulbs (as opposed to cars designed for LED bulbs from the beginning) have to have an LED driver built into the bulb unit. Some aren't designed so well, especially if it's a no-name type, with some just throwing a plain resistor in series with the bulb. The normal flash speed compared to speed with the engine running is likely because the bulb gets 14v plus with the engine running, but only battery voltage with just KOEO (key on/enging off).

So the increased voltage with engine running may be throwing the BCM off - especially because of the unexpected resistance value with poorly designed LED drivers in many "replacement" LED bulbs. This is especially true if it's just a simple resistor in series. As the feed voltage varies, so does the resistance, voltage, and current the BCM receives as "feedback."

That's my theory, and I'm sticking to it.

 

[Certified Drunk]

Put the stock type bulb back in, problem fixed.

 

[American Locomotive]

There is no flasher to replace in a 2011 Grand Cherokee. All computer controlled.

The body computer measures the current going through the bulbs. If it doesn't detect enough current, it assumes a bulb is bad and causes them to flash fast to alert the driver. The LED bulbs do not draw enough current to keep the body computer happy. Who knows why it works with the engine off.

My recommendation: Put normal turn signal bulbs back in. They're cheap and last like 8-10 years. Just replace them all.

 

[darkzero]

They sell resistor "modules" that you can add to the vehicles wiring to add load to "fix" this. A fix for a problem that wouldn't have been a problem but I get it, people like to modify their vehicles, me included (I don't have LED turn signals though).

I wouldn't add them resistors to my car though. They sell "canbus LEDs" for this very reason. Everything is built into the bulb, no modifications to the vehicle necessary. Yeah they cost more but ya gotta pay. Me personally, for turn signals I'd just go with whatever bulb the car was designed for/came stock with.

 

[tarbellb]

Yes, you need to add a resistor. Solves the problem

Go on Ebay or Amazon, super cheap. Use Wago style connectors for a quick fix.

 

[LSU]

Yes, you need to add a resistor. Solves the problem

Go on Ebay or Amazon, super cheap. Use Wago style connectors for a quick fix.

She has the resistors. We wired one in, “solved” the problem but the resistor got to 214f. We decided way too hot to be near the tail light housing, etc.

 

[RTM]

Get the bulb w built in resistor as noted above. Usually a better design, doesn’t get as hot.

 

[mrvm]

Installed canbus LED replacement bulbs on an older vehicle with no issues in the interior, head lights, tail lights and parking lights. Skip the turn signals and avoid all the extra work.

 

[tak1313]

She has the resistors. We wired one in, “solved” the problem but the resistor got to 214f. We decided way too hot to be near the tail light housing, etc.

If a resistor is getting hot, it generally means the power rating is exceeded. For example, using a 1/4 watt resistor when the circuit needs a 1/2 watt (or more) resistor.

Why do resistors get hot?

Resistors are essential components in electrical and electronic circuits. But, sometimes resistors get hot and here is why.

electronicguidebook.com

 

[mv213]

She has the resistors. We wired one in, “solved” the problem but the resistor got to 214f. We decided way too hot to be near the tail light housing, etc.

What is the wattage rating of your resistors? I usually see 50 watts recommended. Too low a wattage rating will overheat.

 

[LSU]

It is a 50 watt resistor. Still getting hot.

 

[tak1313]

Personally, I would just stick with regular bulbs in a car not made for LEDs unless it was an EV car/truck or MAYBE Hybrid (to save on drain), but most of those types are already designed with LEDs in mind (other than stuff like older Priuses (Prii, whatever).

Something like this may work if you really want to stick to LEDs

LED Flashers, Electronic Flashers, Led Protectors & Load Equalizers | Autolumination

The Autolumination provides Led Protectors & Load Equalizers Led Turn Signal Flashers

www.autolumination.com

 

[tarbellb]

Maybe you need French resistors for that Stellantis vehicle

 

[billford]

Some years ago, I had something similar with a combination led signal/brake bulbs. They were also setting a trouble code in the engine computer and a transmission shift issue because of the high resistance in the brake light circuit.

I didn't want to spend too much time on it and wanted that vehicle out of the shop.

I just added small 194 incandescent bulbs in parallel to the led bulbs and hid the 194 bulbs behind the bumper where they could not be seen. This added enough load to the circuit.

Its a mickey mouse repair but it fixed the trouble code and the fast flashing signal light.

I know the leds should have been replaced with the stock bulbs, but the owner wanted to keep the leds because they looked cool.

 

[VolvoRyan]

Problem with resistors is that they do get stupid hot.

Does the Jeep use a dual filament bulb for the corners? If so, you're just going to melt housings.

-Ryan

 

[Xcursion88]

We've fixed these...finicky bastards
I'm not anywhere near the shop at present to look at notes and won't be for a couple days but...

Certain diodes and resistors is what we use and it functions exactly like the non LED bulb.

Moreover we've seen all kinds of weird ****. Your issue to having the dash indicators stay illuminated if not flashing...to fast flashing to no flashing whatsoever.

 

[bubinga]

Op did you ever get it fixed?

 

[no704]

I replaced the turn/brake bulbs on my ‘59 Dodge. Ran standard relays to control them.

 

[LSU]

Op did you ever get it fixed?

Yes. We installed the Resistors (on the wires leading to the trailer lights) - and it solved it.

 

[LSU]

Problem with resistors is that they do get stupid hot.

Does the Jeep use a dual filament bulb for the corners? If so, you're just going to melt housings.

-Ryan

We installed them away from all plastic material.

 

[bubinga]

Only has current through them with the T/S's on.