I've had my 83 300SD for about 1k miles now (242k when I bought it), and the cruise control does not work right.

I read in the manual that you hit the lever up (or down) to set it. When I hit the lever up and release it, the car starts accelerating rapidly, and I have to immediately hit the brake to disengage. When I hit the lever down and release it, nothing happens...the cruise is not set.

Anyone seen this problem before? Is it just a dirty contact in the steering column somewhere?

Thanks

Mark in MA

There is a company that tests and repairs CC amplifiers (located under the steering wheel inside the trim panel/cover-aluminum case ~4"X6"X1.5") AND they list a proceedure on how to test the actuator. If the amp is still good a bad actuator (under the hood) can ruin it. Test BOTH so you don't ruin the amp. If I find the link I'll come back and repost it.

__________________
1987 300D (230,000 mi on a #14 head-watching the temp gauge and keeping the ghost in the machine)
Raleigh NC - Home of deep fried sushi!

That was one of the failure modes in my CC. Resoldering the amplifier board fixed all the problems. There are many threads on this forum and maybe even a DIY describing how to do that. If that's not possible for you, a rebuilt board can be purchased for $200 or so.

Checking/cleaning the actuator, as Mr. Watts says, is also a good idea (and some day I'll do just that ).

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

my cruise control (when it would engage and usually on hot days) would immediately begin to accelerate (i let it go one day and it went to 75, i think) just as you describe. i too heated every solder point on the board of the amp and now it works again.

__________________
MIKE
1987 300D Turbo, 225K
124.133/603.960

Interesting. My 81 240D's cc did exactly the same thing for the first couple of months I had it. Now it doesnt work at all. I think I'll try the re-solder the circuit board thing too.

- Peter.

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2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S

To confirm,
The amp is behind the driver's side lower dashboard on an '83 300SD?

Thanks

Mark

I re soldered all the contacts on my CC amp, it works perfectly now, except when I'm in the wake of a big truck, it kinda freaks out and accelerates the car untill I stop it.

__________________
"spreading a trail of obnoxious where ever we go"
1981 300sd w/ 341,500 miles

http://www.wecrash.com/pics/ddda_banner.gif

You guys are amazing!

I reflowed all the pads on the CCA circuit board and all is well.

The biggest pain was getting the amp out of the vehicle (until I realized that one 10mm socket removes the whole bracket).

Thanks for your help and my cruise is functional again!

Mark in MA

Here you go: http://www.gdl-online.com/testproc.html

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1998 E300 +310,000K
1996 E300 +460,000K