To start, the full set of rear lights are all wired in series.

Great drawing, and, I know I'm not the Internet Police, but, I must say, your drawing shows a parallel circuit, not series. A series circuit would prohibit all lights in the circuit from lighting when one burns out.

 

I got this blue :laugh:

Actually no. He is first of all not showing an electrical schematic, so deriving circuits here is not a possibility. He is merely showing the wiring as it appears on the back of the housing.

In technical sense, the wires tie together inside the plugs and thus provide continuity regardless of bulb status. They are not wiring in series and he does not show it as such.

 

Are the resistors mounted to anything or do they just hang?

 

mine just hang, but should you choose to mount them, mount them onto something metal because they will get hot

 

Is the resistant from one not enough to fool the computer for both bulbs in one housing? If so, would a larger single resistor work verses 2 smaller ones?

 

I too tried just one resistor. It is most definitely smart enough to detect resistance in the circuit between one or two. you need two.

 

one 50W 6ohm resistor wasn't enough. I tried the one before the first bulb first and still got the hyper flashing. I added the second one and it fixed everything.

I'm sure you can use a larger resistor as long as the numbers all match up.

 

You helped me out so much. I had trouble after connecting with quick connector(scotchlock) so i soldered. Works amazing now. So much better.

 

Just for clarification...

The two resistors are wired in parallel so the end result final resistance is
Rtotal = R1R2/R1+R2
R1 = 6 ohm
R2 = 6 ohm
Rtotal = 6*6/6+6 = 36/12 = 3 ohm
so one could use one 3 ohm resistor but you would need to double the wattage rating to handle the additional power lost to heat since the single resistor would need to dissipate the power that the two resistors dissipated before. Maybe not double the original power rating since the original resistors were overrated.

Total power using ohm's law is I = V/R
I = Power
V = 13.5 Volts
R = 3 ohm
I = 13.5/3 = 4.5 Watts round up to next highest rating.

 

yup. Spot on. However, their could be some issue if you do this. First, getting those readily available may be tough as everyone makes them now for the single bulb application. Second..... heat. That just means more heat in one place and that can cause other problems, especially since the old ones are toasty enough.

I did mount mine but I with some prejudice. I use zip tie adhesive pads to adhere to the truck body, then in between the zip tie and the resistor, I looped some shrink wrap to protect the zip tie from melting and to minimize what was covered to allow maximum heat dissipation. So far so good..... but it is winter.

 

I have fixed my comment.

Didn't want to spark an electrical war here. Get it. Spark!!! :lol:

Ok focus!!!

 

Just wanted to add, grey is also the brake light wire. In case someone sees this thread and is wondering which one is brake. It looks like turn signal is just controlled by the brake wire being sent a pulsing/flashing signal.

Per the electrical manual:

When the turn signal/multifunction switch is placed in either the TURN RIGHT or TURN LEFT position, ground is applied to the body control module (BCM) through either the right turn or left turn signal switch signal circuit. The BCM responds to the turn signal switch input by applying a pulsating voltage to the front and rear turn signal lamps through there respective control circuits.

You can see in the chevy electrical diagram it is listed as stop lamp but no turn signal is listed.

Colors in the diagram show different because colors coming from the truck harness (green yellow, brown, white green) are different than the ones on the tail light harness (grey,orange, and yellow)

 

Blue...thank you so much for the diagram, saved me a ton of headaches when doing my install today!

 

A lot of people have asked me about how to add resistors in for anyone who wants to swap out their tail light bulbs to LEDs and prevent the hyper flashing. So I've created this thread for people to reference.

To start, the full set of rear lights are all wired in parallel. So if you open up the wire loom before all of the bulbs, you'll see 4 colored wires:

Black - common negative
Gray - turn signal positive
Orange - tail light positive
Yellow - reverse positive

Using this MS-Paint diagram, you can see that the common ground wire comes out from the truck (big blue block on the left) to the first bulb, comes out of that bulb to the middle bulb, out of the middle to the last.

***NOTE*** The left bulb in the diagram is actually your bottom bulb in the tail light housing



So as you can see here, this is before all of the bulbs, you T-Tap/Splice the resistor to the black wire and the gray wire:


You do the same for the last bulb:


Here is a full picture showing everything.


Any questions???

YES, why use LED bulbs in the tail lights anyway? I can see using them to cut down on power usage but with the short circuit resistors that goes out the window.

Thanks for the info.

 

Because I like the light output and the clarity of LED lights over halogens

 

I did this today and still had the issue of fast blink and notice on the dash. What led lamps are folks using? I am using the diode dynamics 7443's and have used their stuff in every other socket in the truck... want to get this nailed down and thought I'd try here before going back to them. Have their 50 watt 6 Ohm resistors...
Thanks in advance folks.

 

Do you have 2 resistors on each side?

 

2nd gen owners keep asking me if 2 resistors are really needed for the tail lights if you swap over to LEDs. The answer is yes. One of my resistors went bad. Check out my video.

 

I did - but I want to do it again and see if I did something wrong.
Not a fan of the taps, so I am going to do something a bit nicer with solder and shrink wrap... after I make sure it works.

As you noted - one before both lamps and one before the last lamp, correct?
Thank you.

 

That is correct. Just make sure the resistors work. I need to get new resistors.

 

Anyone replace the cargo lights in a 2016? How do you get the lights off with the tape around the housing?

Sent from my iPhone using Tapatalk

 

Never mind. Haha.

Sent from my iPhone using Tapatalk

 

Just wanted to say thanks for putting this out . . made it simpler than I imagined! From my motorcycle days, the LEDS make a huge difference!

 

I just wanted to add that you can tap both resistors in at the back of the first bulb, but the only caution being that you need to make sure that the top black and top grey are connected separate from the bottom black and bottom grey wires (don't cross the resistors).
I did it this way to be able to tuck the resistors back inside the body. The taps are a little tough to get all 4 next to each other though.

 

I did the same, although I re-taped the sleeve to expose another half inch of wire or so. T-taps are enough of a hassle without trying to cram four of them into that kind of close proximity!

It's unfortunate that GM does the hyperflash thing, they could have just gone with the DIC warning (unlike the old days where the fast blink really was an electrical side-effect). If you hit the emergency flashers on an LED setup with no resistors, they'll blink at the normal rate all day long. (Or try the LED turn signals without resistors, you'll notice they blink normally about three or four times before the fake hyperflash sets in.)

Anyway, thanks blue for posting up which wires to tap.

 

And now one for front switchbacks?. Very nice to write-up! Sticky?!?

 

That was done a while ago:
http://coloradofans.com/forums/2645874-post22.html

 

@Blue15ColoradoLT or anyone, if I don't want to add resistors can I simply change the following bulbs to LED's?


Bulb --------------------------------------------GM PN# X-Referance --PN# that may also fit
Tail (Stop) lights ------------------------------7443
Reverse lights ---------------------------------921 ---------------------194 2825L
Cargo & Center High Mounted Stop lamp ---921 -(Three needed)-----194 2825L
License plates ---------------------------------194 ---------------------921 2825L
Interior domes & reading lights -------------194 -----------------------921 2825L
Visor ------------------------------------------30mm festoon ------------?


How about total Qty for above, does this look right? (No turn signal lights wanted)
7443 x2
921 x5 (Or just 921 x10 & no 194?)
194 x5
30mm festoon x2

 

The 7443 will need a resistor. Any stop or turn signal with dual element use will, except the high 3rd brake light.
The vanity is 4 X 6614 LED, but the cool whites are too white, and DD has warm whites at their typical pricing...

 

@Blue15ColoradoLT I used your diagram to install the resistors for the tail lights/ turn signals yesterday on my 2016 and it worked exactly as it should, thank you for the diagram.

And it is true for the 2016s as well the one resistor before the first bulb will not correct the hyperflash, you need both resistors (I trusted the input but thought I would see if only one would correct the problem)

 

I know this is not about LEDs in the headlights but I want to hijack the thread for a second. DO you need to add a resistor if you put LEDs in the headlights?

 

No.
You need resistors on lights that do flashing duties to prevent hyper-flashing, because the LED's don't pull enough juice.
The Low beam of the headlight will need a capacitor though, because it does double duty as the DRL via Pulse Width Modulation (PWM), which can cause flickering and/or premature death. Some LED brands have it built in. DRL cannot be disabled by a fuse pull, as it's operated by the BCM.

 

Hey guys,

I was able to use a single 3 Ohm, 100-watt resistor in the wiring harness for the rear lights. I tapped in just prior to the first light (the bottom one), using the common black and grey wires, as Blue15ColoradoLT drew in his diagram. It works like a charm.

On the left tail light assembly, you'll see two 10mmx1.50mm threaded studs used to mount the tailgate. I made a small aluminum L-bracket, drilled with 10mm holes at 78mm, center-to-center, for mounting the resistor. The resistor was sized to a 4mm hole (not sure what the stock size was, maybe 3.5mm - it was very close to 4mm already). The L-bracket was drilled with matching 4mm holes on one side, and 10mm holes on the other.

I wasn't sure how hot the resistor might get during city traffic (lots of brake light and turn signal use), so I put a small piece of sticky aluminized fiberglass heatshielding on the inside wall near the resistor. That way, the exterior painted surface will have some interior protection from the heat source (i.e. the resistor).

On the right-hand side, I'll need some 10mmx1.50mm couplers to extend the same 10mm studs out a bit. The right-hand side houses the mechanism that lowers the tailgate slowly. I'm not sure what it's called, but appears to be a small drum with viscous fluid and vanes allowing for the slow, controlled fall of the tailgate.

So far, the Diode Dynamics brake lights are crazy bright on the left side. Awesome! I love it. Well, except I'm presently running a mismatched set .. the left is bright LEDs, and the right is, for the moment, stock incandescents.

 

Pics no longer work. Also did you just use one resistor for each side or one per bulb. What rating of resistor did you use

Thanx!

A lot of people have asked me about how to add resistors in for anyone who wants to swap out their tail light bulbs to LEDs and prevent the hyper flashing. So I've created this thread for people to reference.

To start, the full set of rear lights are all wired in parallel. So if you open up the wire loom before all of the bulbs, you'll see 4 colored wires:

Black - common negative
Gray - turn signal positive
Orange - tail light positive
Yellow - reverse positive

Using this MS-Paint diagram, you can see that the common ground wire comes out from the truck (big blue block on the left) to the first bulb, comes out of that bulb to the middle bulb, out of the middle to the last.

***NOTE*** The left bulb in the diagram is actually your bottom bulb in the tail light housing



So as you can see here, this is before all of the bulbs, you T-Tap/Splice the resistor to the black wire and the gray wire:


You do the same for the last bulb:


Here is a full picture showing everything.

Any questions???

 

One for each bulb, so four in total, 6 ohm, 50 watt... two of these kits:

https://www.diodedynamics.com/store...com/store/accessories/led-accessories/resistors/led-resistor-kit-1-reviews.html

(Or three kits for 6 resistors if you're replacing front signals with Switchbacks, too.)

 

Well, at least one of my resistors lasted just 13 days. Luckily I had a spare pair (I had bought a set for my switchbacks up front, then decided to splurge on the running-lights harness). I'm assuming it was a resistor, anyway -- the problem was intermittent but when I removed those infernal t-taps the connections looked solid, clean cuts through the insulators at all points.

While fiddling with the new t-taps, I wondered -- any reason the resistors couldn't be installed in series instead of in parallel with t-taps? I'm guessing the resistance of the LED (the other branch of the parallel circuit) is so low that it's probably irrelevant to the overall resistance. It would be nice to use a plug connector instead of those awful taps.

That also got me wondering, what happens if you install an incandescent bulb with the resistors in place? I was planning to keep my old bulbs as emergency backups.

 

I just installed rear LED's following this thread, works perfect. 2 resisters for each tail light assembly, 1 for each bulb.

 

With the pictures not working, I could use a little guidance.

I was able to install resistors on the top bulb with no issues, as there is only 1 grey and 1 black wire.

However, on the bottom bulb there are 2 grey and 2 black wires (I assume turn signal (+) in and out and ground (-) in and out). On the bottom bulb, does it matter which grey wire I tap for resistor and which black wire I tap (in the absence of the diagram)? If so, could someone describe which wire I should tap (outside-grey or inside-black)...something like that to give me just a little direction please?

 

You want to tap the gray and black "in" wires, since the "out" wires go to the other light.

Tagging @Blue15ColoradoLT to maybe fix the PhotoBucket-hostage pix...