Cruise control "hunting"
 

My '88 300CE cruise control is constantly hunting for the set speed. It's as though there is a short in the system or something, faster then slower at a very rapid pace. Any ideas?
Also is it a big deal removing the drivers door panel to replace a broken door check?
Thanks

Cruise control
 

Is repairing/replacing a broken cruise control difficult? I seem to see that mentioned a lot on the forum. Are MB cruise controls more finicky than those used by other auto manufacturers?

I have a friend whose cruise control is not working (W126). It's not a big issue, but it got me thinking about it. I use mine a lot.

Does it surge? If so, I have the same issue. I'm waiting for a cool weekend day to start hunting this one down. I spoke with my local dealer about it, and they seemed to think replacing the vacuum lines would probably sort it.

Speaking of this, I had rented a 2006 Impala LT over the weekend, as I had to go on a trip and did not want to take my car. I was very disappointed with the cruise control on this car. I had set it on 72 mph, but it was between 70-75 at times. Very frustrating. Something I would not expect for a 2006 car, especially since GM had "perfected" the cruise control system on the 70s and 80s cars. I had a 72' Buick Electra a few years ago and whatever speed I set the cruise on, it would say right there.

Other than that, the Impala was a nice car, but my mother and aunt kept complaining of the seats. One was complaining that the seats were not soft enough and one was complaining of the rear head rests would not let her lay her head back, as they are "fixed" to the seatbacks. Oh well, can't please everyone. Probably get a Ford Five-Hundred next time, to see how it compares, or better yet, a Cadillac DTS.

John Berry said: My '88 300CE cruise control is constantly hunting for the set speed. It's as though there is a short in the system or something, faster then slower at a very rapid pace. Any ideas?
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Seems to me this usually is the cruise control amplifier. Solder connections come loose on the older models. Do a search and I know you'll find all the info you need to either re-solder it yourself or get the correct parts.

My 86 300E did the same thing and it was the amp. Follow Rockman59's advice.

I resoldered mine last year. Worked fine last year, but is back to the way it was again. Is there something about winter storage that affects the solder connections I wonder, or maybe something else that I did when removing it and replacing it that 'fixed' it? I'm fedup with this crappy cruise 'brain' and may try adapting an aftermarket kit to work with the control handle.

Check out your speedometer needle - is it vibrating at all or moving up and down slightly. A stretched or worn out speedometer cable can cause the cruise to "hunt" as the variations seen on the speedometer are picked up by the cruise amp.

Another thing to check out is the brake lights - make sure they are functional and of the correct wattage. This is a common culprit in cruise control failure not "hunting" behavior.

Removal of door panel. Easy after you have done it once.

1) Driver's side. Remove the black sliding piece at the front side of the the
mirror adjuster handle. Remove the adjuster handle.

2) Remove the triangular trim piece that surrounds the shaft for 1) above.
I think it pries out at the top, not the bottom. You might break a plastic pin, but replacement part is cheap.

3) Now remove all the seat adjuster buttons, they pull straight out.

4) Remove the plastic circlip on the largest plastic shaft sticking out.

5) Now remove the rear plastic shell by prying it out at the top.

6) Next take a small screw driver and pop the brass lever that is hooked at the end, upward out of the white plastic female receptacle.

7) Pull the foam back at the top of the arm rest grab and remove the bolt.
Remove the plastic shell that surrounds the door handle.

8) Remove the light housing at the bottom of the door facing the ground.
Disconnect the wires.

9) Roll the window down all the way.

10) Remove the screw that retains the black plastic u-shaped piece at the
rear of the door .

11) Finally you will need to push the panel upwards to release the plastic hooks that lock the panel to the door. Start at the bottom. It may require some force.

12) Take care to not loose the u-clips at the top of the door that the top of the door panel fits into.

13) Unplug the speaker wires.

14 ) Carefully peel back the moisture barrier plastic.

15) Check strap is self explanatory.

Are you impressed that I remembered this?

Don't be I just did it 2 days ago on my '92 300E

Steve

FWIW, the first thing you should do is take all the linkages under the hood (without disturbing their length), pop them off, and flush/clean/lubricate the balls and sockets with auto trans fluid. My cruise worked fairly well, but was a little "jerky" until I did this (as per MB manual).

Thanks for all the information. Where is the amp located? does it come apart easily to have access to solder it?

Did I miss something - why did we get door panel removal instructions?

Last line of OP's Q's: "Also is it a big deal removing the drivers door panel to replace a broken door check?"

Ah - thanks.

I think you'll find this thread useful for replacing the door check:

http://www.peachparts.com/shopforum/tech-help/155585-94-w124-door-panel-removal-door-check-replacement-map-pocket-fix-diy.html?highlight=door+check