[LaughingSuperCruiser]

@MichBolt @ARob @atc98092 Calling your attention to this heavy derail of a very useful, highly trafficked thread that should probably have clarity over time and not, whatever this was/is. I could not have been taken more out of context in my intentions. I made a joke about GM engineers being good at cost cutting down to technicalities of regulation at the expense of what some believe, our potential safety. I was not calling out anyone personally. Apologies again to both @LaughingSuperCruiser and @pkaso .

There really is no need for an apology. Your opinion is as good as my opinion. I think the word "shiv" is what prompted me to comment.

When I was making changes mandated by management to save costs (or more commonly to eliminate a schedule hit) I came to understand that there are tradeoffs. What good is the perfect product if nobody buys it because it costs too much? Especially in the technology area where advancements happen very quickly, being a year or more late on a product can have dire consequences on your ability to develop future products. Most engineers want to make the very best product they can design. The joke in R&D/Product Development is that if left up to engineers you would never ship a product. There are always improvements that can be made.

Anyhow, I agree with other posters. Let's get back to the discussion of this interesting modification to the lighting of the EUV. I am not planning on implementing it, but this type of discussion is exactly why I am on this forum.

 

[Oxyno]

Diodes ordered. We'll see how this goes....

 

[no-gas]

Can someone please share the link to the diode devices?

 

[a priori]

Can someone please share the link to the diode devices?

I did the diode mod on my 2022 EV. Guess I'll have to look into doing this on an EV since it is a little different than the EUV. Should be possible. Thanks for the info!

Edit: Ordered the PWM dimmer with bypass. I'll update with my progress and pics on an EV vs. an EUV.

Diodes ordered. We'll see how this goes....

I thought the OP said this mod was done without diodes.

I'm no electrician and not an EE, so I'm probably missing some critical knowledge. But I have to say that as much as this mod sounds useful and interesting, I cannot made heads or tails of the procedure to get it done. The other one showed a great video and step-by-step description of what to do. But that one still left out the possibility of showing more braking activity once the lights were activated (or so I have thought).

Perhaps someone will be able to do this mod and show a similar step-by-step video (and give a parts list). I'm sure I could engage a friend or two to help me make the modification. It seems like it would enhance safety without compromise.

 

[stangbat]

I thought the OP said this mod was done without diodes.

There are no diodes on the mod discussed on this thread. The device being discussed is made by "Diode Dynamics" and is called "Automotive PWM Dimmer With Bypass." So some posters are referring to the device as a diode. It isn't.

 

[mmascari]

I thought the OP said this mod was done without diodes.

A more nuanced statement might have been "without simple diodes".

A Google search for the product name returns this: 2A LED PWM Dimmer with Bypass (pair)

It's an entire little module which also contains a diode but much more than just the diode too. Instead of "simply" joining the extra power supply to the running lights, this module is installed instead. The module has a Low input, High input, Ground, and Output connections. Changing the normal running light input to go to through the low and connecting the output to the light then, will cause the normal running light operation to be lower (dimmed). Then, connecting the brake like input to the high, will cause the running light to light up at full brightness.

In the pictures, you can see the device was connected so the output only impacted the running lights on the hatch and not the ones on the side of the car, which is also different than the other post about wiring these up.


If I could snap my fingers and have any solution, I would like to see a replacement light assembly with and additional even brighter braking light. Alas, that's probably not going to happen. The solution above will certainly give you 2 light levels, but even at full bright, they're the same as the side lights. There is at least an intensity change when the brake is first applied.

 

[no-gas]

There are no diodes on the mod discussed on this thread. The device being discussed is made by "Diode Dynamics" and is called "Automotive PWM Dimmer With Bypass." So some posters are referring to the device as a diode. It isn't.

Sorry, I am not a EE but I what I meant was the link to the PWM "diode dynamics" tdevice that was used by OP and sold on Amazon (or elsewhere)

 

[stangbat]

Sorry, I am not a EE but I what I meant was the link to the PWM "diode dynamics" tdevice that was used by OP and sold on Amazon (or elsewhere)

Poster above you referred to ordering "diodes". Hence my comment.

The device: https://www.amazon.com/gp/product/B085B9LZSS/

 

[no-gas]

Thank you! This will the first mod when I receive my EUV...

 

[pkaso]

Can someone please share the link to the diode devices?

Sorry for late reply
i got from amazon

Amazon.com: 2A LED PWM Dimmer with Bypass Pair Diode Dynamics : Automotive

Buy 2A LED PWM Dimmer with Bypass Pair Diode Dynamics: LED & Neon Lights - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

ebay

2a LED PWM Dimmer With Bypass PR Diode Dynamics DD3018 for sale online | eBay

Find many great new & used options and get the best deals for 2a LED PWM Dimmer With Bypass PR Diode Dynamics DD3018 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

or company

2A LED PWM Dimmer with Bypass (pair)

Features Easily accomplish a low/dimmed level and a high power signal on nearly any automotive LED device. Assembled in USA Overview This is a set dim level 12V PWM dimmer, perfect for automotive use with dimming on the positive channel. Most other dimmers operate by modulating the negative...

www.diodedynamics.com

Its expensive for what they are but i check Alibaba and AleExpress, cant find exact unit. There are similar by function but they are not enclosed (circuit board only) no wires and dimming knob big.
You need 1.5-2 feet wire to connect dimmer ground to chassis ground.

 

[Jim99]

I’m guessing that this mod will require two units; one for each tail light. Is that correct?

 

[pkaso]

I’m guessing that this mod will require two units; one for each tail light. Is that correct?

Yes, i use 2 dimers, its sold as two on amazon.
It is possible to use one (dimmer can handle 2 Amp, 2-gate run lights 700 mA) but i didnt try.

 

[a priori]

A more nuanced statement might have been "without simple diodes".

A Google search for the product name returns this: 2A LED PWM Dimmer with Bypass (pair)

It's an entire little module which also contains a diode but much more than just the diode too. Instead of "simply" joining the extra power supply to the running lights, this module is installed instead. The module has a Low input, High input, Ground, and Output connections. Changing the normal running light input to go to through the low and connecting the output to the light then, will cause the normal running light operation to be lower (dimmed). Then, connecting the brake like input to the high, will cause the running light to light up at full brightness.

In the pictures, you can see the device was connected so the output only impacted the running lights on the hatch and not the ones on the side of the car, which is also different than the other post about wiring these up.


If I could snap my fingers and have any solution, I would like to see a replacement light assembly with and additional even brighter braking light. Alas, that's probably not going to happen. The solution above will certainly give you 2 light levels, but even at full bright, they're the same as the side lights. There is at least an intensity change when the brake is first applied.

Thank you. Very helpful response.

 

[Rainystateguy]

Perhaps i should record youtube video like the one with diode fix.

Please do so, if it is not too much bother. That would be quite helpful. This looks like it is possibly a great solution.

 

[Raxstone]

You should probably read what this thread is actually about.



No it's actually what they did. This isn't debated. This is why you have things like steel panels on the EUV and aluminum panels on the EV. They needed to cut costs because they were losing money (and may still be) on each Bolt EV they sold. That's not debated either, it was rumored at release and confirmed by Mary Barra herself in I believe 2019.

Whether or not the brake lights functioning like this as a result of wiring reduction, that's speculative. But I think decently guessed speculation.

They already has wire harnesses designed that DID work with the tailgate lights as well as the lower lights. They revised the harness for 2021 with the EUV. That revision cost MORE than simply continuing to use the already available harness. Reusing existing materials is always cheaper than developing new materials. Yet, not one body panel or trim piece is reused from the EV. That seems to blow your theory out of the water.

 

[Raxstone]

I made lift gate tail lite work like STOP light, sorry pictures not in order

I didn’t notice any reference - do the tailgate lights also now function for signaling?

 

[pkaso]

I mod my 2023 Bolt EUV LT tail light (on lift gate only), i follow somebody else post but instead of diodes i use:
" Diode Dynamics" Automotive PWM Dimmer With Bypass, i got from Amazon, its sold by pear and i use each dimmer for left and right tail lite on lift gate.
easy job if you have hands and eyes (not color blind).
You can access the wires by removing top plastic trim on lift gate.
The three wires you need to locate are: (i copy from someone post)

• Instruction and connection for dimmer self explanatory ones you read instruction and see picture:
• The brown/yellow stripe wire powering the 3rd brake light (connect 2 high power red wires)
• The gray/brown stripe, right tail light
• Purple/gray stripe, left tail light (it look to me purple/wight stripe), the are 2 the same color at big connector, choose the one opposite site from gray/brown wire.
• Run small wire to ground nut, 1.5-2 feet.
• Adjust tail light brightness (i dim to max).
• Each tail light draw 350mA so total 750mA

I you you know haw to solder wires its 1-hour job.
I wish i can post more picture, but they allow 10 only.
I am happy with this set up, but you do at yours own risk.
I dont encourage anybody to make changes this is illustration purpose only.
Sorry for not professional post, doing first time.
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I found good youtube video about EUV Run and Stop lights:

 

[RacerX00]

They already has wire harnesses designed that DID work with the tailgate lights as well as the lower lights. They revised the harness for 2021 with the EUV. That revision cost MORE than simply continuing to use the already available harness. Reusing existing materials is always cheaper than developing new materials. Yet, not one body panel or trim piece is reused from the EV. That seems to blow your theory out of the water.

Steel is cheaper than aluminum, that's not a theory. Wire costs money, there's a lot of it in cars, that's not a theory.

What I'm saying isn't being debated, by anyone, really, just you. GM definitely wanted to get the costs down on the EUV as they were astronomical on the EV. It's also not conspiratorial to conclude GM put the higher trims on the EUV and restricted them and various features from the EV for this specific reason, to push more customers towards the higher profit margin EUV.

The wire harness "they already has" is not applicable here, and the EUV introduction was MY22, not 21. I'm not even sure why you're telling me GM did this if not for cost cutting reasons. The guy who came on here and got defensive for engineers didn't even fight me on the reason why, he took issue with the prison knifing thing.

Has a nice day sir.

 

[deanhatescoffee]

I didn’t notice any reference - do the tailgate lights also now function for signaling?

This mod only makes the tail lights act like brake lights, not turn signal lights.

 

[pkaso]

This mod only makes the tail lights act like brake lights, not turn signal lights.

Yes
You are correct, i am looking to do simular fix to run lights on the body of the vehicle (not on the gate) to function together with turn signal (bumper stop/turn light) but it will depend on dificulty of implementing.
I am looking at posts about trailer lights to get idea where wires are.