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Four Brake lights and turn signals

SabreXray

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eecyclone said:
Thanks for that. My thinking is that when I did this I was wiring the taillight upside down. So I think there is a chance that the top light flashes and the bottom bulb stays bright when the turn signal and brake are both on. Oh well, same difference right?
Yep, I agree, either way would look nice.

-Sabre
 

eecyclone

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I think this would be my favorite mod that I've done so far but I never get to see it!  :E:
 

BlazerPride

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I'm passed that. Enjoyable for a while.
Now, I drive in and watch my DRL's flash with the turn signals.  :cool:
 

BlazerPride

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Troublemaker said:
Wigwag, or at the same time?

Same time. I modded the outlet, so my DRL's are on LOW, (full-time, of course), and flash with turn signals on HIGH.
Modding the socket does take time. But, I like the look.
 

Z66Modder

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I've been having some serious current draw issues with this mod when I'm stopped at a light. With the rear defroster, heater blower, wipers, headlights, FTDRL's sail panel lights, Line of Fire, and interior LEDs all on and I hit the brakes, the engine struggles. I already upgraded to a 140 amp alternator but it still struggles. It might be a bad diode so I am going to reverse this mod and limit the sail panel light to running only to see how much a difference it might make. It's kinda overkill with that super bright cascading LOF anyhow.
 

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Z66Modder you may want to check your battery,
 

Z66Modder

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Thanks, It's a Costco battery with a 60 month warranty so I may take it to them.
 

MS03 2500

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Naw get a good battery, when GM designed these trucks they never meant to have them draw big power like the all on hi lights. I had the same problem when I put a Nav. You may want to take off the ground wire on the frame and clean them.
 

Dads04Z71

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I?m a little late to the party for this great mod.  First, you guys with the pristine trucks, no doubt in the south west ? I?m jealous as hell.  I hope they stayed that way in the many years since the pictures were posted.  The undercarriage of my 04 A/V looks like the Titanic  :(  due to all the road salt and brine used here in NE Pa.

I understand the wiring diagram prepared by JHC in reply 10.  However, instead of only one rear light blinking when the signal is applied and the brake is applied, I want to keep both lights blinking.  In other words, I do not want one brake and one signal light when both are applied.  This scenario was touched in replies 96 & 97. 

Has anyone modified JHC?s original mod to work the way I would like?  If so, can you post a schematic or diagram?

Thanks in advance.

 

JHC

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The easiest way to accomplish that would be to cut the wires going to the brake lights and turn signals, connect the wires from the lights together and attach them directly to the trailer harness. No diodes needed since they will work the same as trailer lights.
 

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Many thanks JHC.  Makes perfect sense.  Now I just need to wait till winter is over here.
 

Dads04Z71

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JHC said:
The easiest way to accomplish that would be to cut the wires going to the brake lights and turn signals, connect the wires from the lights together and attach them directly to the trailer harness. No diodes needed since they will work the same as trailer lights.

JHC: While I am waiting for the snow and mud to go away and the temps to get out freezing and low 40s to do this mod, I did a little research on the alternative we discussed.  From what I can determine from the wiring diagrams (in the A/V Shop Manuals) - there is only one flasher module to handle vehicle turn signals, trailer turn signals and the 4 way flashers.  This brings to mind two questions:

1. If I cut the rear signal lamp and brake wires and connect them together (on the bulb side) and then connect the combined connection to the appropriate trailer harness wire, will the signal flasher module detect the original and now dead end signal wire as a burnt out rear signal lamp and give a fast flash?  If so, I would have to put a resistor load (how much?) to ground on the cut wire.  Yes?

2. I am wondering how the four way flashers will work with the rear brake and turn signals running totally of the trailer harness circuit?

Many thanks.  Joe

 

TheAtheistReverend

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Dads04Z71 said:
JHC: While I am waiting for the snow and mud to go away and the temps to get out freezing and low 40s to do this mod, I did a little research on the alternative we discussed.  From what I can determine from the wiring diagrams (in the A/V Shop Manuals) - there is only one flasher module to handle vehicle turn signals, trailer turn signals and the 4 way flashers.  This brings to mind two questions:

1. If I cut the rear signal lamp and brake wires and connect them together (on the bulb side) and then connect the combined connection to the appropriate trailer harness wire, will the signal flasher module detect the original and now dead end signal wire as a burnt out rear signal lamp and give a fast flash?  If so, I would have to put a resistor load (how much?) to ground on the cut wire.  Yes?

2. I am wondering how the four way flashers will work with the rear brake and turn signals running totally of the trailer harness circuit?

Many thanks.  Joe

I want to do the same thing as you. Have you had any luck with finding answers to your questions?
 

Z66Modder

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JHC said:
Here is the drawing
index.php

I used this original setup and have both bulbs as turn signals on each side.
 

TheAtheistReverend

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Z66Modder said:
I used this original setup and have both bulbs as turn signals on each side.

But only when brakes are not applied, right?

JHC said:
I connected all 4 lights to work with the brakes and the turn signals. When the turn signal is on, only the top light functions as a brake light (as normal) and when the brakes are applied, only the bottom light functions as a trun signal (as normal).

But if the brakes are applied and the turn signal is not on, I have 4 brake lights and if the brakes are not applied, I have 2 lights for the turn signal on either side.

I'm hoping for both lights on each side to function as one. Brake, park, turn, only one function per side at a time.
 

Dads04Z71

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@TheAtheistReverend  - you asked "I want to do the same thing as you. Have you had any luck with finding answers to your questions?"

No - even though JHC said it would work.  Being a car guy from the 60's and having done a lot of car re-wires and mods and working with computers and electronics all my life, and understanding how computers and solid state devices work in vehicles, I'm not convinced just cutting the brake/turn signal wires to the rear lights and then connecting the lights to the trailer harness circuit won't introduce other problems even though the both lamps will light for either braking or turn signal.

Unlike the 4 on high mod, which can be undone in less than a minute by just pulling the diodes, this mod requires cutting, soldering, etc and if it doesn't work right under ALL conditions, then we have a safety issue.  Plus, having no load on the cut, and no longer used rear turn and brake signal wires, has to be detected by the turn signal module.

Since this is a much more involved mod (the way I want it to work), somewhat difficult to undo and can cause a possible safety issue (rear lights not working correctly) I decided to leave well enough alone.  There is also the factor that if I sell my A/V (unlikely) the new owner will have no idea of the mod nor how this mod was made.

PS.  I saw someone say old Avalanches never die, they just go faster.  Unfortunately, in my case, it will rust out long before that.
 

Z66Modder

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Yes you are correct, only both are turn signals with the brake off. You could add a relay on each side that cut off the brake signal when the blinker was on but it would wig wag them. Be pretty cool actually.  (y)



Dads04Z71 said:
PS.  I saw someone say old Avalanches never die, they just go faster.  Unfortunately, in my case, it will rust out long before that.

Maybe in your case its: Old Avalanches don't just die, they rust Faster.  >:D
 

Dads04Z71

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Thanks.  I should have added to my earlier response (above) to TheAtheistReverend another concern I had with connecting the brake and turn signal wires directly to the trailer harness.  I do occasionally trailer (not often) and with their additional load, along with now adding trailer lights, will the the trailer harness circuit as well as the related trailer signal flasher be up to the task?

This is one of those things, with this mod, I don't want to discover or solve on the day I hook up a trailer.

And in my case (I'm past 70 years old) it a race as to who will rust out first.  Me or my A/V.  In either case, neither one of us will be going any faster. javascript:void(0);
 

Z66Modder

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Sperry mentioned 2/3 of the available current for the trailer lights would be consumed by the tail lights if powered alone by the trailer harness. Add in a trailer load and it would be too much. The load for the cut wires could be simulated by adding LED load resistors found at most auto parts stores. This setup would most likely only work if you never towed.
 

TheAtheistReverend

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Z66Modder said:
Sperry mentioned 2/3 of the available current for the trailer lights would be consumed by the tail lights if powered alone by the trailer harness. Add in a trailer load and it would be too much. The load for the cut wires could be simulated by adding LED load resistors found at most auto parts stores. This setup would most likely only work if you never towed.
Thanks for that info! I was going to look up how much was available and how much is likely be used. I do want to end up putting LEDs in the tail/brake lights, and would hope that would be enough less of a draw to save the circuit when towing.

Good points though about the trouble vs potential risks, which is why i had asked if anyone had successfully done what I'm looking to do. Guess I might have to "pioneer"...

But it isn't high on my list if things to do right now since I am not comfortable that I've found LEDs that would function well as tall/turn/brake lights.
 
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