[you27]

Just checked all the lights on my 2017. The tail and stop lights are all on the tailgate, not the bumper. So what changed for 2022? Was there a rule change, as I read somewhere previously, that prohibits the stop lights from being only on the tailgate? If so, can somebody provide a reference so the problems that causes can be addressed? Another reason why I'm going to keep my old one for a while longer, and probably won't replace it with a new Bolt.

Does suggest that raiding a junkyard Bolt for tailgate components might be productive, if you want to DIY a fix.

There are red sections of the light bars (which include the turn signals and backup lights - making the turn signals a bit inconspicuous from the rear) in the bumper. They are not illuminated - presumably just reflectors.

Rules have not changed. GM just decided to do a design change and got rid of the switch that activates the lights on the bumper when the hatch is open. Probably a cost cutting measure. The EUV technically has outer light sections that are not on the hatch, so they could have designed turn signals and brake lights on the outer section of the running lights. But again, probably cost less to have 1 design for both the EV and EUV.

 

[Frajit]

2022 and 2023 EUV Tail Light Mod

Note the OP's excellent video shows how to modify the tail lights on a 2023 EV. For those of us with 2022 and 2023 EUVs, the wiring on the back side of the lift gate is significantly different. I discovered this only after removing all the trim panels (breaking a side peg) and finding there is no easy access to the wiring leading to the tail lights like on the EV. That was the bad news.

The good news is you can do this mod on an EUV without removing any of the trim. You can access the wire to middle brake light and both the left and right tail lights within the bundle of wires the OP exposes in the video when peeling back the rubber boot on the left above the lift gate frame. The three wires you need to locate are:

• The brown/yellow stripe wire (same as in the video) powering the 3rd brake light
• The gray/brown stripe and purple/gray stripe wires leading to the tail lights

(Sorry, no pics. I had already buttoned everything back up before realizing I should have taken some.)

I soldered a diode between two short (2"') lengths of wire, then soldered two more short lengths to the wire on the downstream end of the diode. I then soldered the upstream end of the wire to the 3rd brake light wire, and one of the two downstream wires to each of the tail light wires. I double-checked the insulation at the solder points, tucked the wiring into the boot and then reattached it.

With this modification the tail lights on the lift gate and the adjoining tail lights on the body of the vehicle illuminate when braking. Note also the front running lights will also illuminate. As described in the video, the front running lights and rear tail lights illuminate only if the parking lights or headlights are off. If those lights are on nothing will change when braking as the lights are already illuminated.

Doing this modification entirely within the rubber boot has two advantages. Obviously it is far less work in that you don't have to remove and reattach the four trim panels around the lift gate - a real PITA. Another advantage is that the wiring mod is hidden from view beneath the boot, so even if the trim panels are removed the mod isn't visible. This might make it less likely to run into issues with voiding the warranty if a tail light burns out while still covered.

 

[stangbat]

If the desire is to brighten the two back lights on the tailgate when the brakes are applied, would it be possible to reduce their intensity under normal headlights-on running with a pulse width modulator or even a resistor inserted into the circuit driving them from the headlight relay? Then, when the 3rd brake light comes on, the intensity of these two other lights would increase as 100% duty cycle voltage would be coming thru the diode used in the modification that started this thread. However, this would reduce the light intensity of the two tailgate lights for normal night driving, so should not be carried to extremes.

I suppose this idea could be used individually to also make these two lights work as extra turn signals at the expense of a more elaborate modification and more wire fishing.

BTW has anyone checked the current thru the diode to make sure it does not exceed the diode's 1 Amp nominal rating? I might be tempted to use a Schottky diode just to lower its power dissipation and get every little bit of the voltage.

I don't have my Bolt yet, so I am curious about what others are able to find out. I do really like the function of this modification as I had nor realised the brake light problem when I took my test drive.

The problem is that the tail lights already aren't as bright as the brake lights. I think trying to further reduce the brightness when they are on at night would be a lot of work for not a lot of benefit.

I didn't bother to measure amperage, but I can't imagine that you're exceeding 1A. I could have easily measured it though. Wish I'd thought about it at the time just for kicks.

This was discussed in another thread, but LED brightness doesn't vary a lot when voltage is reduced. You have to drop voltage quite a bit to see a noticeable difference in brightness. You can verify this with a variable power supply. If you don't have that, just try adding and removing 1.5v batteries to a 12 v LED. You'll be surprised how little difference 1.5v makes in the overall brightness. The extra voltage gained from using a Shottsky diode would be completely unnoticeable.

 

[Electric Personality]

2022 and 2023 EUV Tail Light Mod

Note the OP's excellent video shows how to modify the tail lights on a 2023 EV. For those of us with 2022 and 2023 EUVs, the wiring on the back side of the lift gate is significantly different. I discovered this only after removing all the trim panels (breaking a side peg) and finding there is no easy access to the wiring leading to the tail lights like on the EV. That was the bad news.

The good news is you can do this mod on an EUV without removing any of the trim. You can access the wire to middle brake light and both the left and right tail lights within the bundle of wires the OP exposes in the video when peeling back the rubber boot above the lift gate frame. The three wires you need to locate are:

• The brown/yellow stripe wire (same as in the video) powering the 3rd brake light
• The gray/brown stripe and purple/gray stripe wires leading to the tail lights

(Sorry, no pics. I had already buttoned everything back up before realizing I should have taken some.)

I soldered a diode between two short (2"') lengths of wire, then soldered two more short lengths to the wire on the downstream end of the diode. I then soldered the upstream end of the wire to the 3rd brake light wire, and one of the two downstream wires to each of the tail light wires. I double-checked the insulation at the solder points, tucked the wiring into the boot and then reattached it.

With this modification the tail lights on the lift gate and the adjoining tail lights on the body of the vehicle illuminate when braking. As described in the video, they illuminate only if the parking lights or headlights are off. If those lights are on nothing will change when braking as the tail lights are already illuminated.

Doing this modification entirely within the rubber boot has two advantages. Obviously it is far less work in that you don't have to remove and reattach the four trim panels around the lift gate - a real PITA. Another advantage is that the wiring mod is hidden from view beneath the boot, so even if the trim panels are removed the mod isn't visible. This might make it less likely to run into issues with voiding the warranty if a tail light burns out while still covered.

Too late now, but pics would have been awesome!
Regardless, on the short list.

 

[BoltyMcBoltFace]

Just checked all the lights on my 2017. The tail and stop lights are all on the tailgate, not the bumper. So what changed for 2022?

For 2017-21, the tailgate lights are the primary brake lights, but if you drive with the tailgate open, it switches to using the lights in the bumper since they will still be visible. That's the regulation at play here, and I don't think it has changed. For 2022, they redesigned the tail lights and (likely) decided to save a few cents per car by removing the brake light function from the tailgate. I share the opinion of many here that it was a horrible decision. I appreciate the at least partial fix provided here.

 

[Raxstone]

The problem is that the tail lights already aren't as bright as the brake lights. I think trying to further reduce the brightness when they are on at night would be a lot of work for not a lot of benefit.

I didn't bother to measure amperage, but I can't imagine that you're exceeding 1A. I could have easily measured it though. Wish I'd thought about it at the time just for kicks.

This was discussed in another thread, but LED brightness doesn't vary a lot when voltage is reduced. You have to drop voltage quite a bit to see a noticeable difference in brightness. You can verify this with a variable power supply. If you don't have that, just try adding and removing 1.5v batteries to a 12 v LED. You'll be surprised how little difference 1.5v makes in the overall brightness. The extra voltage gained from using a Shottsky diode would be completely unnoticeable.

You might not be able to get pics of the wiring but you could still include a pic of where you actually accessed the wiring.

 

[Frajit]

You might not be able to get pics of the wiring but you could still include a pic of where you actually accessed the wiring.

I'm not sure you are addressing this to me since you quoted another poster. However, in case you are, here's a photo of the "boot" at the top of the lift gate frame where I accessed the wiring for the left, right and 3rd brake lights.

 

[Deant]

Hello folks,

I recently bought a 2023 Bolt EV and noticed when braking or slowing down, SUVs and trucks would appear to roll right up to my rear end as if they were not going to stop. This is especially true during stop and go traffic. Wife also noticed this and asked me to check the tail lights because she thought it might be broken. To my surprise, only the bumper mounted lights would turn on when braking. The lift gate light only activates when the parking light or headlight was turned on.

I searched the internet for a kit or replacement tail gate light that would have dual function as brake and parking lights but there was none. I decided to modify the Bolt's lift gate lights to turn on when the brake lights are activated. The lift gate lights had 1 level brightness and was not as bright as the bumper mounted brake lights but at least it would help add visibility. I did check for any digital or data signal on the positive voltage line and confirmed there was no signal. I believe these LED lights are not design to require any maintenance so the factory probably felt it was not necessary to monitor it's status anymore. "No more burn out incandescent bulbs to check for."

Note: When the parking light or headlight is turned on, the lift gate light would also be on so stepping on the brakes will not make any changes in brightness.

I made a video of the entire process. The modification was purposely done to be as simple as possible and not to include the turn signal function. There were 2 parts that was challenging for me.

1. Removing the gate pivot "one time use" plastic bolt with out breaking them. I had to use a a pair of pliers to slowly pull it out of the lift gate. I modified these to make sure they can easily be removing the next time I needed to remove these plastic trim plates. In case anyone breaks the pivot, the part# is 42363844
2. Re-installing the lower large trim panel. The retainer pins was difficult to align while holding the lift gate in place. I found that loosely closing the rear hatch on top of the lower trim panel help hold it in place while I snap all the retainer pins back in place.

The intent was to make sure bigger vehicles can see that I am braking or slowing down. Here is a simplified wiring diagram of the connection.

View attachment 48081
In case anyone breaks their Shade pivot plastic bolt, here is the OEM par tnumber. 4236844

Its on youtube:

The modification have worked really well. i do notice SUVs giving me much more buffer room now.

Good article. Identifies a problem and presents a solution. Here’s a related NHTSA article: Rear signaling | National Highway Traffic Safety Administration (NHTSA)
I will check with my dealer about the vehicle warranty.

 

[RacerX00]

I really thought this general sentiment would have had them fix the tails in 2023 MY, but nope!

 

[BoltLookie]

The problem is that the tail lights already aren't as bright as the brake lights. I think trying to further reduce the brightness when they are on at night would be a lot of work for not a lot of benefit.

I didn't bother to measure amperage, but I can't imagine that you're exceeding 1A. I could have easily measured it though. Wish I'd thought about it at the time just for kicks.

This was discussed in another thread, but LED brightness doesn't vary a lot when voltage is reduced. You have to drop voltage quite a bit to see a noticeable difference in brightness. You can verify this with a variable power supply. If you don't have that, just try adding and removing 1.5v batteries to a 12 v LED. You'll be surprised how little difference 1.5v makes in the overall brightness. The extra voltage gained from using a Shottsky diode would be completely unnoticeable.

I'll grant that the Schottky diode won't do much better than the 1N4001 if the current is much lower than 1 A. I was more thinking of the diode heating up less because of the lower Schottky forward drop, e.g .3 Watts for the Schottky vs .7 Watts for the 1N4001 if both are carrying 1 Amp.

Interesting about the light intensity of the LED LEFT/RIGHT Tail Lights not varying much with supply voltage. Of course raw LEDs have a very strong increase in light intensity with voltage, being basically forward biased diodes with light intensity proportional to the forward current, in other words light intensity increases exponentially with voltage, at least as the hockey stick curve breaks. In most circuits they are used with other component(s) to limit the current, the simplest being a resistor and going up to a constant current regulator. With either method I would guess that a pulse width modulator on the supply voltage would reduce the light intensity pretty well as long as the current regulating circuit doesn't have too much capacitive filtering.

I would be very interested to see how current is regulated in the Bolt LEFT/RIGHT Tail Lights. If anyone has looked at the circuit, please fill us all in. I would also be very interested to know if anyone has tried to fish the turn signal circuits up into the hatch back to allow the LEFT/RIGHT Tail Lights to flash with the bumper lights for turn signals (and for brakes).

I do appreciate the simplicity of the mod in the original post. A lot of bang for the buck, so to speak.

Again, looking forward to playing with my Bolt when it arrives.

 

[stangbat]

I just noticed something. After this mod when you apply the brakes and the hatch tail lights illuminate, the rear side marker lights also illuminate.

 

[Frajit]

I just noticed something. After this mod when you apply the brakes and the hatch tail lights illuminate, the rear side marker lights also illuminate.

Yes, I pointed that out in my post above (#42). I was pleasantly surprised to see that they also illuminated.

 

[noobla3]

I just noticed something. After this mod when you apply the brakes and the hatch tail lights illuminate, the rear side marker lights also illuminate.

If someone can make those turn signal that would be nice. I'm still hesitant to make this mod if it doesn't work when the headlights are on. Will there be a solution to that?

 

[stangbat]

If someone can make those turn signal that would be nice. I'm still hesitant to make this mod if it doesn't work when the headlights are on. Will there be a solution to that?

I doubt it. It wouldn't be easy at all. The current tail lights aren't designed to illuminate at two different levels of brightness. It would most likely take custom parts and tail lights and someone programming and designing a module to make things work they way they used to (and still should).

I don't understand being hesitant. When the headlights aren't on, you have extra protection in arguably the case when it is needed most. When the headlights are off, everything is the same as it was, which is not great, but it isn't any worse. I'd like it to also work with the headlights on, but I'll take what I can get and be happy with it.

 

[Frajit]

I don't understand being hesitant.

Agreed. Don't let perfect be the enemy of good.

 

[usedBolt]

I doubt it. It wouldn't be easy at all. The current tail lights aren't designed to illuminate at two different levels of brightness. It would most likely take custom parts and tail lights and someone programming and designing a module to make things work they way they used to (and still should).

I don't understand being hesitant. When the headlights aren't on, you have extra protection in arguably the case when it is needed most. When the headlights are off, everything is the same as it was, which is not great, but it isn't any worse. I'd like it to also work with the headlights on, but I'll take what I can get and be happy with it.

Would the lights from older Bolts fit? They do have 2 sections, 1 for tail light and 1 for stop.

 

[stangbat]

Would the lights from older Bolts fit? They do have 2 sections, 1 for tail light and 1 for stop.

No, totally different shape and size.

 

[noobla3]

View attachment 48092

My rear glass isn't tinted. Do you think this can work inside the lower portion of the rear glass? Sort of like the third brake like but in the bottom portion.

 

[you27]

My rear glass isn't tinted. Do you think this can work inside the lower portion of the rear glass? Sort of like the third brake like but in the bottom portion.

I thought about that. Technically you could, but the light won't be straight. The bottom of the glass is a curved and part of the center part will be blocked by the rear wiper.

 

[noobla3]

Yes, it definitely doesn't look as nice as the deck lid installation.