Disclaimer
The community here at 355nation.net urges you to please use caution and seek professional assistance when performing modifications to your vehicle. Before attempting any modification it is advised that you refer to your Colorado or Canyon service manual or contact a certified mechanic as not all GMT355 trucks are the same. The staff and the associated members are in no way responsible for any damages, injuries or other harm inflicted to your vehicle or yourself which may result in attempting these modifications. The posts and content presented on this site reflect in no way the views of 355nation.net or it’s ownership.
![Image]()
A 355nation How To presented by
Skidude010
Project Name
LED Switchback Front Turn Signals
Project Description
Modifying a 3157 LED white/amber switchback bulb to fit in the 3757 socket of the front turn signals
Skill Level
Eeasy
Project Vehicle
Make: Chevrolet
Model: Colorado
Year: 2007
Engine: 3.7L
Power windows: YES
Sun Roof: No
Tools Needed
100 Grit Sandpaper OR dremel
Project Time
30 minutes or less
Project Cost
$80 + shipping
This is a simple "How-To" on a cheaper option for making your front turn signals LED switchbacks. This means your turn signal bulbs will be white then blink amber when the turn signal/caution lights are engaged.
Our front turn signal sockets are made to fit a 3757 type bulb which has an offset side tab configuration as shown below:
![Image]()
LED switchback bulbs are only made with a 3157 tab configuration (at least I haven't found any in 3757). The 3157's have a center tab placement like below (pictures of an unmodified 3157 bulb):
![Image]()
![Image]()
Step 1:
Purchase your white amber switchback turn signal bulbs. I grabbed these from V-leds.com for $49.99 + $5.00 shipping for the pair. According to V-leds these are NOT recommended for use if your DRL bulbs function as your daytime running lights. Mine is an 07 so my daytime running lights are the headlights.
http://www.vleds.com/6k-type-2-dual-color-changing-white-amber-switchback-42-high-power-led-turn-signal-bulbs-3157-4157-1-pair.html
Step 2:
Take your sandpaper or dremel and shave down the half of each tab of the 3157 LED switchback bulbs so that they become offset like the 3757 bulb tabs. Sand until they will fit snug into the 3757 turn signal socket. A dremel would make this quick and easy but sand paper will work. All I had was 100 grit sand paper so that's what I used. In the pictures above you can see a center seem in the plastic, this is what I used as a guide on where I needed to stop sanding. The pictures below are of the modified switchback 3157 bulb.
![Image]()
![Image]()
Step 3:
Make sure they work. These bulbs will only work one way in the socket, so if at first they do not light up, take the bulb out, flip it, and reinsert into the socket.
I purchased this pair for $29.99 + shipping as a matching set for the inner DRL bulbs next to the turn signals. These are a direct fit for the inner sockets so no shaving is required, but they also will only light up if inserted one way into the socket, so if they do not light up at first, flip the bulb as described above.
6K WHITE 54 LED BACK-UP/PARKING LIGHT BULBS 3157 3156 4057 4114 | 1 PAIR
![Image]()
I apologize for the shaky video. I wanted to demonstrate the switchback in action which meant reaching in through the window of the cab to hit the turn signal while trying to hold the camera.
NOTE: Hyperflashing may occur if you have LED brake light bulbs in your tail lights.
The community here at 355nation.net urges you to please use caution and seek professional assistance when performing modifications to your vehicle. Before attempting any modification it is advised that you refer to your Colorado or Canyon service manual or contact a certified mechanic as not all GMT355 trucks are the same. The staff and the associated members are in no way responsible for any damages, injuries or other harm inflicted to your vehicle or yourself which may result in attempting these modifications. The posts and content presented on this site reflect in no way the views of 355nation.net or it’s ownership.
A 355nation How To presented by
Skidude010
Project Name
LED Switchback Front Turn Signals
Project Description
Modifying a 3157 LED white/amber switchback bulb to fit in the 3757 socket of the front turn signals
Skill Level
Eeasy
Project Vehicle
Make: Chevrolet
Model: Colorado
Year: 2007
Engine: 3.7L
Power windows: YES
Sun Roof: No
Tools Needed
100 Grit Sandpaper OR dremel
Project Time
30 minutes or less
Project Cost
$80 + shipping
This is a simple "How-To" on a cheaper option for making your front turn signals LED switchbacks. This means your turn signal bulbs will be white then blink amber when the turn signal/caution lights are engaged.
Our front turn signal sockets are made to fit a 3757 type bulb which has an offset side tab configuration as shown below:
LED switchback bulbs are only made with a 3157 tab configuration (at least I haven't found any in 3757). The 3157's have a center tab placement like below (pictures of an unmodified 3157 bulb):
Step 1:
Purchase your white amber switchback turn signal bulbs. I grabbed these from V-leds.com for $49.99 + $5.00 shipping for the pair. According to V-leds these are NOT recommended for use if your DRL bulbs function as your daytime running lights. Mine is an 07 so my daytime running lights are the headlights.
http://www.vleds.com/6k-type-2-dual-color-changing-white-amber-switchback-42-high-power-led-turn-signal-bulbs-3157-4157-1-pair.html
Step 2:
Take your sandpaper or dremel and shave down the half of each tab of the 3157 LED switchback bulbs so that they become offset like the 3757 bulb tabs. Sand until they will fit snug into the 3757 turn signal socket. A dremel would make this quick and easy but sand paper will work. All I had was 100 grit sand paper so that's what I used. In the pictures above you can see a center seem in the plastic, this is what I used as a guide on where I needed to stop sanding. The pictures below are of the modified switchback 3157 bulb.
Step 3:
Make sure they work. These bulbs will only work one way in the socket, so if at first they do not light up, take the bulb out, flip it, and reinsert into the socket.
I purchased this pair for $29.99 + shipping as a matching set for the inner DRL bulbs next to the turn signals. These are a direct fit for the inner sockets so no shaving is required, but they also will only light up if inserted one way into the socket, so if they do not light up at first, flip the bulb as described above.
6K WHITE 54 LED BACK-UP/PARKING LIGHT BULBS 3157 3156 4057 4114 | 1 PAIR
I apologize for the shaky video. I wanted to demonstrate the switchback in action which meant reaching in through the window of the cab to hit the turn signal while trying to hold the camera.
NOTE: Hyperflashing may occur if you have LED brake light bulbs in your tail lights.
