WHT Z06 Mods: Garage Door Opener

WHT Z06 Modifications:
Garage Door Opener

Garage Door Opener

C6 Corvettes with higher trim levels come with a garage door opener built into the driver's side sun visor. The Gentex Homelink was used for 2005 through 2007 vehicles built before November of 2006. Later 2007 through 2013 have the Lear Car2U. Both products are learning remotes with similar features however it has been observed that the Homelink has better range than the Lear and it is also compatible with a larger number of garage door opener models.

It's easy to identify which type you have; both have three buttons but the Homelink has a single LED (surrounded by a little house icon) and the Lear has three LEDs.


Gentex Homelink	Lear Car2U

After noticing that the Lear that came with my Z06 only had about 50 feet of range, I did some research and learned that Homelink has better range. Looking at ebay there appeared to be two upgrade paths to the Homelink. One was to buy a sun visor from a 2005 or 2006 C6 Corvette. The other was to buy just a Homelink unit and install it in my original sun visor.

Homelink Versions

There are two versions of Homelink that fit into the C6 visor: HL3 and HL4. The main advantage of the HL4 is that it works with Chamberlain, Liftmaster, and Craftsman openers that have Security+ 2.0 technology (introduced in 2011). In addition to using a rolling code, Security+ 2.0 uses three different RF frequencies (310, 315, and 390 MHz), probably to improve range and reliability.

(Speaking of versions, apparently Lear switched from Gen I to Gen II remotes in 2012.)

There were a few reasons I decided to replace the opener in my original sun visor. First, it was the only way to get a HL4 Homelink. Second, the airbag safety label on 2005-2006 visors is different from 2007-2013 visors and I wanted mine to match. Finally, it's the least expensive way to go. But it's also a lot of work to swap remotes because you have to remove the stitching from the visor and then later sew it back up. Any decent upholstery shop can re-stitch using the original holes. But I used a different technique.


Homelink HL4	Remote Swap

Machine Stitch By Hand

The most common sewing machine stitch uses threads on the top and the bottom of the piece. The machine pokes the needle into the piece and the bobbin passes the bottom thread through the top thread. Then the needle comes back up and the process repeats. The top thread crosses under the bottom thread. Here's a short animation that shows how it works (In case it's not clear).

How a Sewing Machine Works

What I figured out is that it's possible to replicate this stitch by hand. All I needed was a sewing machine needle and some decent thread. I used Güetermann Original Sewing Thread (Extra Strong 110 yards/100 meters) and a size 90 needle. I started by pushing the sewing machine needle with the top thread through an existing hole (made by an industrial sewing machine at the factory) and then pass the bottom thread through the loop of top thread. I removed the needle, pulled both threads tight, and moved on to the next hole. The result looks as good as new (if anything, the Güetermann thread I used is higher quality than the original).


Stitch Detail	Complete

I can now open my garage door when within 150 feet of the opener.

Homelink Programming

The 2007 C6 Corvette owners manual contains instructions for both Homelink and Lear openers. Here's my take on the Homelink programming process:

Erase All Existing Programming (Optional)
To reset the Homelink to a completely unprogrammed state, press and hold the two outside buttons until the LED starts flashing or until 20 seconds has passed.
Reprogramming a Button
Press the Homelink button and observe the LED. If it flashes slowly, the button is unprogrammed; release the button and proceed to the next step.
If the Homelink LED says on solid or flashes rapidly when you press the button it is already programmed. Continue pressing the button until the LED starts flashing slowly (which indicates learning mode). Continue pressing and proceed to the next step.
Per-Button Programming
With the garage door opener remote 1 to 3 inches away from the Homelink, press and hold the desired Homelink button and the opener remote button at the same time. The garage door will open or close and the Homelink LED will flash slowly and then rapidly as it learns from the opener remote. Once the LED flashes rapidly, release both buttons.
Now press the Homelink button and observe the LED. If it stays on while pressed, you have a legacy garage door opener and it should open or close. If it flashes rapidly, your opener uses a rolling code system (congratulations) and you need to proceed to the next step to program your garage door opener.
Rolling Code System Programming
At this point you have taught the Homelink what kind of rolling code system your garage door opener uses. Now you need to teach your opener to recognize your Homelink.
Your garage door opener should have a "smart" button. Press it until you see some indication that the opener has entered learn mode. Then go back and press the Homelink button for two seconds and release for one second. Repeat until the garage door opens or closes. This process can take two or three presses. If you have trouble, refer to your garage door openers manual. Assuming you programmed the Homelink button correctly in the previous steps, the Homelink is just another opener remote as far as your garage door opener is concerned.
Note that you only have 30 seconds to complete the garage door opener learning process; if you take too long, start this step again.

If you have a Chamberlain, Liftmaster, or Craftsman garage door opener with Security+ 2.0 and are unable to program your opener to work with Homelink you might have a HL3. In this case you will need to buy a Homelink repeater kit. The repeater consists of a unit that you put inside the car and a receiver unit that is installed near the garage door opener. Then you teach the car unit to recognize your Homelink and then teach your garage door opener to recognize the receiver unit.

I do not believe any C6 Corvettes came with the HL4 version of Homelink. Here are some reasons:

The 2007 C6 Corvette owners manual explicitly references the HL3 FCCID (CB2SAHL3).
The FCC database shows that the "equipment authorization" for the HL4 (FCCID CB2SAHL4) was granted in April of 2006. The Corvette factory usually begins production in June the year prior to a given model year. The 2007 model switched to the Lear Car2U in November. It's unlikely the HL4 version was available during this window.
The oldest manufacture date I've seen for a HL4 browsing pictures on ebay is July, 2007. This is well after November, 2006.

My conclusion is that C6 Corvettes switched from the Homelink HL3 directly to the Lear Car2U.

Sun Visor Removal and Installation

I have the factory service manual but the section on how to remove and install sun visors is worthless. What I found useful were some of the videos on youtube. After removing and installing a couple of visors, here are some notes:

The left and right visor mounts are mirror images of each other.
The factory states that the bezel cannot be reused. While the installation and removal process does incur some wear and tear on the bezel, I've always been able to reuse the original.
For removal, you want to position the visor about 1/2 way between the windshield and door window. Then insert a screwdriver into the slot in the bezel and pry/rotate the visor towards the door window.
Once you pop it loose, carefully work the visor down; the bezel will likely come out with the visor.
Release the connector with a small screwdriver (or a fingernail).
For installation, first remove the bezel from the visor. You'll probably need to rotate it.
The hole in the roof that accepts the bezel is triangular. The bezel has four fingers, three of them match the hole, the fourth is used for alignment.
Once you figure out the proper orientation, insert the bezel, making note of the location of the longest finger.
Now look at the bezel and the mating piece on the visor. You'll see there is a square raised section on the visor that is supposed to match up with a square recessed area on the bezel.
You want to insert the visor about 1/2 way between the door window and the windshield. You also want the tallest stud to be closer to the door window than the windshield. The idea is you will be rotating the visor (and thus the tallest stud) towards the windshield and you want the tallest stud to rotate and align with the tallest bezel finger and have the square sections to snap together.
Rotate the visor towards the windshield, applying some upward pressure to the visor, stopping when it clicks into place.
Don't be discouraged if it takes a few tries.

Other Homelink Information

It appears that the optional garage door opener C7 Corvette, which is still located in the sun visor, is a HL5.
Homelink HL4 and HL5 openers can be controlled via a LIN bus (ISO17897). For the HL4 opener I installed, the bus is on the unused center pin.
Homelink HL5 supports two-way communications. When paired with a compatible two-way garage door opener (MyQ and AssureLink models) the Homelink is able to indicate the last known status of the door.