MDC/Smart Madness Cruise Control Problem

aflyby · 06-13-2009, 08:24 AM

I installed the MDC unit with LED about a month ago. Only used it a couple of time before yesterday. When first installed the LED flashed till I hit the stalk end button, the LED glowed steady and set the speed with the rotator ring. Speed boster set on '3'.
Yesterday, I hit the stalk end button, LED goes steady, BUT the cruse sets speed at 45, prior to this I had to use the rotator ring. I thought the Button was merely an ON-OFF switch.
The the situation deteriorates. Driving at 45 mph with cruise on, I come up upon a slight incline. NOT a 6% upgrade, just a slight incline. The speed dropped of to 43 mph and the the cruise quits and the red triangel in the speedo starts flashing an exclamation point!!!!!. I pull of the road before becoming a sand hauler's hood ornament. I have no cruise, the accell pedal is not responding, and a flashing red triangle. I think it went in LIMP-HOME road.
Put it PARK, shut off engine, waited 2 min. and tried a restart. Same conditions exist. I then shut engine off, remove key, step out of the BRABUS, lock the car, wait 5 min ant unlock the car, try a restart and everythin is operating normally.
Drive home retrace the instal and all is correct. Reset speed booster to '1' and hit the road. Same place on road and same thing happens. ON-OFF switch set the speed, hit incline and then, No pedal response, flashing red triangle. Turn off engine and do the exit, lock, unlock, restart thing and once agin all is fine. Tried a run on Interstate 10 at 70mph and same problem happens at incline. Any ideas???

piglith · 06-13-2009, 10:31 AM

How much of an incline? If you were to not use the cruse and go over the same incline with your foot on the peddle with out accelerating, how much speed do you drop? Does the car seem to need to down shift to make it over the incline? It sounds like something is causing the unit to trip off. All door, ebrake, seatbelt and airbag functioning correctly. I know it doesn't like it when this stuff acts up. It is posable it is just a bad module. Only problem Ive had with it on inclines is it will actually speed up then come back down to speed after going over. Maybe set the speed boost back to off and pull the ground on the battery to reset things and see how things go that way.

John_H · 06-13-2009, 10:49 AM

The unit should maintain speed even if it lags for a few seconds unless you experience an extreme situation. Going into limp-mode sounds like something's miswired. Perhaps the "connector" inside the module mating with the factory harness connector is intermittent. I'd check all connections - internal and external - for a good mechanical fit.

Some have expressed the need for a tie-wrap in the right place. I have an Area451 so I can't recall the MDC particulars. If all the wiring is sound, however, there's a slight possibility that handling the open module was enough to cause some ESD damage (electro-static discharge) which is causing some failure in the unit. This might be a simple warranty issue.

I hope you get it all cleared up quickly!

red mnm · 06-13-2009, 11:51 AM

I am not sure I can provide much insight into why your ! on the speedo comes on, but I may be able to assist with why the CC disengages. The MDC unit has a 'feature' called 'disengage after accelerate'. Why it has this I have no idea

, but I do know from experience if you accidently set this feature the CC will not hold the speed on any incline up or down. As soon as the accelerator is released the CC cuts out if this feature is on. Fortunately there is an easy remedy. You probably set this just like I did when I was trying to set the Sprint Boost. To see if disengage is 'engaged' you need to start the car just like you were going to adjust the SB. Push the CC On button and hold for about 10 sec. The LED should change to a steady color. If the steady color is RED

you have the Disengage engaged. Just push the CC button once before it goes out to toggle it to GREEN

normal CC operation. Turn the car off wait 30 seconds, and the CC should function normally. If the LED is GREEN when you first get to 10 secs, then there is some other problem and I would you suggest you contact Smart Madness about the problem.

aflyby · 06-13-2009, 03:14 PM

Thanks for the feedback. I did try a non-cruise run on the same inclines and was able to maintain speed at 45 with very little extra throttle. At 70 mph I needed about twice a much throttle but nowhere near full throttle to maintain speed. I'll try the described reset when I get home to the car. Thanks

Woody14619 · 06-16-2009, 03:46 PM

I've never seen a red triangle... are you talking about the one in the centrer of the console? I've seen it flash yellow, but never red. I'd double-check the connection to the pedal first off, and make sure the plugs are solidly connected in the box and at the back of the pedal. It could be a defective unit, with such an odd behavior, but I'm betting it's a wiring issue.

The fact that you were not using the end-cap button to engage makes me think you have something wired wrong though. You should need to use the end cap to engage cruise every time you start the car. It's the only way to enable cruise initially after a cold start. If you're setting it with an up-down flick, something's not right, since that should put you in the previous mode (nothing on a cold start) or limiter mode (LED is red).