Purpose: To illustrate how owners can utilize an unused instrument cluster spot as a secondary cruise control indicator.
Difficulty: If you've tinkered with electronics then it is not particularly difficult. Soldering skills are helpful.
Cost: $5 to $10
Warranty implication: Modifying the product of course voids the warranty for the component(s) you modify and any damage to the vehicle is obviously your responsibility. With that said, it is our estimation that the likelihood of causing any problems with the car is very low and damage to the cruise control is completely avoidable with reasonable care.
READ THROUGH THIS ENTIRE TUTORIAL AND ASK ANY QUESTIONS YOU HAVE BEFORE PROCEEDING! And don't proceed if you don't feel comfortable doing so.Summary: Tap into the red (cathode) and black (anode) wires of the cruise control switch cable and run a common LED bulb into a cavity found in your car's instrument cluster, illuminating an unused icon that is there.
Tools and Materials required:
- Discrete LED (see specifications below)
- 4 to 6 feet of 20 to 24 AWG wire
- Splice taps (optional)
- Soldering iron and solder
- Wire cutters/stripper
LED Specs: Color as per your preference. Max 20mA. Forward Voltage between 1.85V and 2.5V. 3mm seems to be a good size (3mm and 5mm are the two most common sizes). In the tutorial, we use one with a 125mcd (brightness) rating but you can buy > 1000mcd if you want brighter. Whatever your local electronics store has is probably suitable.
Step 1: Remove the instrument cluster.First you simply grasp the instrument cluster (ie. speedometer) with both hands and tug straight toward you. Only two basic clips hold it in place. Once removed, you then disconnect the single cable going into the back. This is done by rotating the gray swing arm 90 degrees to unlock then pull the connector straight out.
Step 2: Disassemble the instrument cluster.First you take off the decorative frame at the front. Be careful, but there's really no trick to it - you just carefully pry it loose. It is held on with several somewhat delicate clips.
Next you pull down the lower hinged part of the main plastic body as shown. It is held in at both sides but a little finesse with your fingers and you should have it free with little trouble. Not much force required so if it isn't coming try pushing gently in different directions to get it to unlatch.
Now to remove the electronics from the plastic body. In total there are 7 clip points holding the plastic body on. All have to be loosened for it to come out so if it isn't coming, double check that one you loosened hasn't found its way back into place. With all 7 loose, it should separate with little issue. To get the three white ones in the back, use a small screwdriver or similar tool and gently push the white areas in (don't force!). To get the two on the front simply pry the plastic away from the "guts" gently until it pops. Note the first picture only shows 1 clip. The other one (not shown) is on the other side of center.
Next you drill a hole of appropriate size for the LED you have chosen. The hole goes either into the upper right cavity as shown, or the one next to it depending on your car. Both of our early-release cars have an "ECO" icon in both positions but if yours has the preferred cruise control icon, it will probably be in the 2nd position from the top. If you pry the circuit board up a little you can easily see where the cavities are and shining a flashlight down the channels should reveal what the icons are.
Solder two wires to the LED and tape it appropriately (if you aren't into electronics at all, please enlist someone to help so you don't fry something by causing a short circuit). Be sure to mark the wires or use different color wire so you know which side is the cathode and which is the anode (tip: the vast majority of LEDs have a long lead and a short lead. The long lead is the anode). It is wise to think of how much wire you might need and probably double it... better too long than too short. Once you've soldered and taped your LED, go ahead and stick it in the hole you drilled. Try to make it so the LED is pointing as straight down the "tube" as possible for best light transmission but don't shove it all the way to the end.
Feed the other ends of the wires through a hole in the back and close everything up (the picture shows us using an existing hole but that may not be the best idea if it can cause pinching of the wire. Consider drilling a new hole instead). Be careful putting the plastic housing back on and make sure all 7 clips find their ways back to the proper places.
Feeding the wire from the upper part of the dashboard down the few inches to the lower part (where the wiper arm is) was probably the hardest part of this, but as this picture shows it is possible. A stiff wire would really help here if you have one handy.
With the wire fed through and the instrument cluster cable reconnected, you can push the cluster back onto the dash. Just line it up and push lightly and it should go securely back into place. Now we get into the tricky parts. You need to expose the wires in the cruise control switch cable. There are various ways you can go about this and you may find the simplest is to just cut the wire and splice everything back together afterward. I used a good quality auto-ratcheting wire stripper to strip the outer sheathing away in two places and then carefully used a razor blade to slice and remove it, thereby exposing the three internal wires as shown.
Remember that you marked the wire to keep the anode and cathode separate, right? Tap the anode wire into the black cruise wire and the cathode wire into the red cruise wire. There are a variety of ways to do this. You can strip a section of the wires and solder them or you can use tap-splices like I did. Tap splices come in a few styles, these are high quality ScotchLok taps by 3M. The green one is used to truly "tap" a wire (split off a signal without interrupting that signal) while the red ones are really just fancy butt connectors. You would use the red one on the red wire IF you want to disable the existing LED. In other words, cut the red wire and leave the original LED disconnected. Use the green one if you want the original light to illuminate as well. The black wire must remain connected in either case. You do
nothing with the white wire!
You're pretty much done! Depending on how you did your tapping/splicing you may want to wrap it all up in electrical tape and/or use nylon zip straps to make sure too much strain isn't on the connections. Then put everything back together and go for a test. You should see the appropriate light come on the dash. Some cars will show the "ECO" like ours does but many (most?) should show a little cruise control symbol. Both of these stem from when smart was being indecisive about whether the MHD (pseudo-hybrid) version or the cruise control would be available... in the end it was neither. For those that think a cruise light in the dash might mean a factory cruise is on the way, keep in mind that the "light" doesn't even have an associated LED on the circuit board so don't get too excited. They were just covering their bases and got production under way before decisions were made.
By the way, you can test without actually driving or even cranking up the engine by just putting the key to auxiliary power, shifting into D with your foot on the brake and then press the button... the light will flash because it doesn't like you pressing the brake and button at the same time.
Troubleshooting: I'll add to this as people run into problems and ask questions but here are a few that come to mind.
Problem: Light doesn't come on.
Solution: Perhaps the anode and cathode for your LED are reversed. Try switching the two wires and see if that helps. The bulb could be the wrong voltage or designed for a different power system, etc. Or it could just be a bad bulb. You may have missed a connection - check again. If you didn't disconnect it... does the original light still come on? That may help in your troubleshooting.
Problem: The light comes on but it doesn't look very good. (sort of like ours in the last picture above)
Solution: The dash was designed for a specific LED and it is a surface mounted one that sits in a very exact way and shines directly at the icon from behind. So LED position can make a big difference and you may want to play with pushing the LED in further, or pulling it back, or adjusting the angle. If none of that helps then maybe using an LED that is more or less bright can help. There are also a myriad of LED bulbs with different viewing angles, light intensities, etc and it may just take some trial and error to get it to look perfect. There was a reason, after all, why we put the LED on the stalk instead of making this mod part of the standard installation.
Problem: Uhoh! I managed to damage the cruise cable when trying to remove the outer insulation (or whatever).
Solution: Don't worry about it too much. There's nothing overly special about that wire so if you are handy with soldering you can probably manage to fix it on your own. If not, you will be able to purchase a replacement switch cable from us directly. Price and availability of spare parts are yet to be determined but the expensive part is the main cruise box so it shouldn't be too bad.
Problem: Uhoh! I managed to damage the instrument cluster when [insert major oops here]!
Solution: Ouch. Let this be a lesson to others to proceed carefully! A new instrument cluster will set you back quite a bit. So if the damage is just cosmetic or you broke a clip, try to fix it best you can with glue and/or paint or whatever is necessary. I've had our instrument cluster apart and put back together probably over 30 times now and it is still in perfect condition so the key is to never force anything, take your time, and pay attention to details.
