I love my recently purchased 1991 560 SEL dearly, but I think it tried to kill me the first time I took it on a trip longer than the 25 miles it takes me to get to work. I was travelling down the highway and had the cruise control set to 65, got slowed down by some other vehicles, then engaged the resume function on the cruise control to return to speed. Since this was a slightly inclined segment of the higway, I was not suprised when the throttle opened all the way up and it shifted into passing gear, however when this behavior remained intact after an impressivley short amount of time for the car to reach 100 mph... I began to get a little worried. By the time I was doing about 120 mph, I was more than stressed. After doing a great job of giving my front left brake rotor a nice high-speed warp, I was able to trip off the accelerator pedal by using the tip of my foot from beneath it. (Yes, I checked that there were no obstructions causing the accerator to stick.) I experienced this on a couple more occasions until I could break myself of the habit of using the resume function. The cruise control works perfectly otherwise. Could anybody give me any ideas on what this may be... or is my car really trying to kill me?

so it basically gunned the gas itself and didnt let go?

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99 C43
98 S420
99 C230K
01 C240

Hello,

You will need a new cruise control module. Mine never went to the extreme yours did, but very similar issues. I would also inspect your throttle linkage just to make sure everything has been greased in the last decade and is working smoothly.

Some places sell refurbished cruise control units, new they are a little expensive. Until then, forget about cruise and make sure to tell anyone else who drives the car. You can also pull the unit now if it's a concern, someone else is going to have to refresh my memory on it's location.

Matthew

Yep, it put the pedal to the metal and darn near put me in the back seat... haven't felt anything like it since I helped a friend back in highschool shoe-horn a Ferrari engine into a Triumph TR7... it was still pulling hard at 120. I will start looking for a new CC module ASAP. There is a great Mercedes "reclaimation yard" here just outside of Memphis... or should I go for the new part just to be safe?

Hello,

Honestly I had the same thoughts of finding a used one out of a parts yard. What stopped me was the number of people I've talked to that had the same problem. It just isn't worth having an old part do the same thing when someone else is driving the car. God forbid an accident happens over it.

Go for one that is refurbished and don't have that doubt in the back of your head.

Matthew

I had a strangely similar incident on my 85 380se. Turned out to be the linkage getting stuck on the spark plug wire harness. All was fine until the accelarator was pressed more than about half way. If i got on the pedal too hard it would stick and I also had to lift the pedal with my foot! Did the exact same thing with the cruise. Only when I hit resume after slowing quite a bit. These cars accelerate pretty hard to get back up to speed so I imagine the pedal goes quite low. I tied the harness away from the linkage with a wire tie and it never happened again. Worth a try!

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U. S. Air Force Air Traffic Controller
"U gotta keep 'em separated!!"

The cruise problem I had with my 560 was that it wouldn't shut off. I had the cruise set and hit the brakes to prepare for my upcoming exit. As long as my foot was on the brake the cruise was disengaged, soon as my foot was off the cruise resumed, seeking 85 where it had been set. Kinda scary as you are coming off the highway onto a crowded off-ramp. My problem was the stalk/switch itself not the amp.

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Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.