I completed installation and road testing of an after-market drive-by-wire cruise control system for my 2006 Exige.
The installation was done in keeping with my "mod" requirements where the mod: must look and operate like it is OEM; must not make any permanent alterations to the car (no drilling into the car or cutting of factory wires); must be completely reversible. Unfortunately, this approach takes a lot more time for planning and installation, and in this case there was no information available for prior drive-by-wire cruise control installations in a U.S. 2006+ Elise or Exige. A repeat installation could be completed in about two or three hours assuming the installer is competent. All of the installation work is done on the driver's side of the interior and it does require the installer to be nimble enough to get into the foot well and under the dash.
The cruise control kit installed in my 2006 Exige is made by John Gold International BV, an automotive electronics manufacturer based in the Netherlands that sells its products through a network of independent distributors in Europe. I bought the cruise control kit through UK distributor Conrad-Anderson and paid about U.S. $515 (price depends on daily currency exchange rates), and I was not able to locate any U.S. dealers. Here is the link to Conrad Anderson's web site ---> http://conrad-anderson.co.uk/product...ommand-modules
The "Gold Cruise" drive-by-wire kit is an aftermarket product that works just like OEM cruise control. It uses a control module to send speed commands to an electronic module that interfaces with the accelerator potentiometer. Pressing either the clutch or brake pedal will cancel cruise control mode.
Installation is plug-and-play with a couple of exceptions. Some electrical connections to the cruise control electronic module must be made the old fashioned way: connecting to a switched power source; connecting to both sides of the brake switch; connecting to the speed signal wire of the OEM wire harness at the stereo. The most complicated electronic part of the cruise control installation is also the easiest and is handled by a plug and play harness that connects the cruise control electronic module to the car's accelerator potentiometer under the dash.
Note: installing a cruise control kit requires the installer to mess with the electronics of your car's drive-by-wire throttle and brake systems, and screwing up the installation could mean all sorts of trouble with your car, an accident or possible injury or even death. Find a competent and reputable automotive installer if doing this stuff is beyond your experience level or you are a person that is unwilling or unable to hold yourself responsible for your own decisions or actions.
Below are the drive-by-wire cruise control components that I ordered plus some of my installation tips. Conrad-Anderson has a tech line in case you buy the kit and have questions or need help.
GC90 electronic module: I placed the electronic module in the chassis cavity located above the driver's dead pedal using industrial grade velcro strips and positioned the module so that the wire harness clips face the outside of the chassis and the diagnostic LED of the module faces the foot well. Note: there is little clearance between the steering column knuckle and underside of the dash, so make absolutely sure that any GC90 harness wires (power, brake switch, and clutch switch) lay flat against the backside or underside of the dash, are secured, and are routed around the steering column knuckle as much as possible.
GCT230 T-harness: I routed the T-harness from the accelerator potentiometer to the GC90 module under the dash from the accelerator area to the chassis cavity where the GC90 was placed, with the T-harness held in place with plastic adhesive clips. I secured the T-harness adapter (where the OEM accelerator potentiometer plug connects to the T-harness) to the underside of the dash with Velcro to keep it from drooping down into the foot well. Note: make sure that any T-harness wires lay flat, are secured, and are routed around the steering column knuckle as much as possible.
CM7 control module: I chose this particular dash mounted control module instead of the typical control stalk after deciding that a control stalk mounted on the steering column would likely get kicked and eventually damaged by my getting in and out of the car.
I considered placing the CM7 on the starter switch panel, but that panel is slightly curved and the resulting fit might be goofy. So, instead I fabricated an ABS panel for the CM7 and located it in the storage nook between the driver's door sill and the steering column. First, I made a cardboard template and tweaked and trial fitted it until satisfied. Then, I cut out 1/8 in. ABS plastic with a Dremel and shaped it using a heat gun to form the panel. The panel presses into the rear slot of the dash aluminum tray and is held in place with a Velcro tab on the left side and at the top front edge of the panel. The CM7 wire harness is routed around the rear of the dash partition via the large rear channel along the back of the aluminum dash tray.
The CM7 has a single LED that lights up to indicate that the cruise system is turned on, the LED changes color when cruise is engaged, and the three buttons light up in the dark. The speed lettering on the buttons shows reference kilometers (KM) instead of miles per hour (MPH), which is no biggie to me but might be to you.
Clutch switch: I ordered a clutch switch but it did not come with a bracket, so I fabricated one specifically for the Lotus that eliminated any drilling or use of epoxy. There are two preexisting 1/8 in. holes located on the underside of the dash just in front of the clutch pedal pivot. I used 1/8 in. ABS to fabricate a bracket to hold the clutch switch and fixed it into position using 1/8 in. x 1/2 in. long aluminum rivets in the two aforementioned holes. Make sure that the clutch switch bracket does not interfere with the action of the clutch pedal return spring. Also, I fabricated a small "L" tab that wraps around the front of the clutch pedal arm to ensure full contact with the clutch switch, and the "L" tab is secured to the clutch pedal arm using 3M double sided tape.
I chose ABS plastic because it is lightweight, easy to work with, and I have a lot of it in stock. Aluminum would make a good alternative material to use for fabrication because it is relatively inexpensive, easy to find, lightweight, and easy to work with.
Some additional installation tips:
Speed signal - Sourced it from the speed sensor wire in the OEM harness to the stereo. My car uses an aftermarket adapter harness to connect the OEM wire harness to an aftermarket stereo (Kenwood eXcelon 895), so I inserted a male terminal into the unused port of the speed signal wire on the adapter.
On my initial test drive, the speed signal was too weak for the cruise control system to engage and hold the cruise speed. I referred to the troubleshooting section of the installation manual and installed the kit's optional resistor (bundled with the unused yellow wire of the GC90) between the power (orange) and speed signal (blue) wires as per the instructions. The resistor solved the issue, and the cruise control system engaged and held cruise speed flawlessly after that.
Brake switch - It is located under the dash between the back side of the dash and the pedal cluster. I made my electrical connections to the brake circuit at that location, but you could tap into the brake wires elsewhere (refer to the Lotus electrical diagram). The brake switch is a hassle to get to; however, the brake switch harness is held in place with wire ties that are routed through plastic bases attached to the underside of the dash. The wire ties can be snipped (and later replaced with new ones) so that you can drop the brake circuit harness to drop down into the foot well. Make sure you have good lighting and a clear line of sight before you start snipping!
Power wire - Find a switched power source (refer to the Lotus electrical diagram). I sourced switched power from the auxiliary fuse panel that I previously installed.
Programming the GC90 - Follow the manufacturer's instructions. There are two set up sequences required to perform to program the GC90 module: the first set up reads the car's accelerator potentiometer and can be done in your garage or driveway; the second set up reads the car's speed signal and requires a lightly travelled road where you can pull over to perform the set up sequence and then get up to speed (at least 45 mph). Note: the brake lights circuit must be active as part of the GC90 programming set-up sequences, so turn your key to the ignition position (rather than key-in / accessory position) and leave it there (without starting the engine) while completing each programming set-up sequence. If the brake lights circuit is not active, the GC90 programming set-up sequences will not be initiated.
Road test the cruise system on the open highway where you can repeatedly test the on/off, speed increase, speed decrease, resume speed, brake release, and clutch release functions.
I look forward to using cruise control when returning home tired from a track day or when on a road trip!