I hate these amps.
 

I really do.

Some of you have followed my cruise amp adventures, you should see the pile of them I have. I've had one or two that worked tolerably long term. Still using my retrofitte aftermarket unit personaly. Anyway..

I stumbled across yet another 300sd at work, hidden in the weeds(don't ask), 85 model. Naturaly I went for the cruise amp, saw it was unusualy clean. It's dated 10 of 98, no MB marks, just VDO, not a rebuild. The part number does not match anything else I've seen or can find reference to either, but it's very much like an 86 SDL amp internaly, just newer and cleaner. Naturaly, it does not work either. The amp is from 98, the inspection sticker on the car ran out in 2000(it's wrecked). The stinking amp that probibly cost someone a small fortune is dead after barely two years use. This has just left me shakeing my head. I might pull the servo later just to test it's amp draw, maybe someone stuck a new amp on an ailing servo and killed it. It still bugs me.
Just thought I'd share.

Wolf, I think you had a good idea to just s-can the VDO CC stuff in an ealier thread and go with something aftermarket that will probably be more reliable in the long run. It'll probably be less expensive anyway.
I still admire your perseverance to keep trying to keep it all OEM at any rate. I've given up after trying to work on one amp.

Wolf-walker,
thanks for this post. I was just about to hit the archives. I've got a 78 300SD with an inoperative cruise control. It worked for a split second once, but shows absolutely no sign of working again. I've used aftermarket cruise control in my VW Quantum TD with good luck. I guess I'll pick up another one for my MB.
What are you using for your vehicle speed signal on the aftermarket cruise? The same one that feeds the OEM system?
Joe

I think Wolf is using a pickup and magnets attached to the driveshaft. You shouldn't have any trouble using the stock VSS though, I did it that way (it was pin 11 to my cruise amp, but I think your older car has a 10-pin connector. Check a wiring diagram to find the right one).

I had my amp rebuilt by Becker Electronics in either South or North Carolina back in 1995. They used to advertise in Hemmings. I had a rebuild actuator put in in 1999 or 2000 (I cannot remember, and my repair booklet with the exact date is not in my office). In 1995 the car had less than 200kmi, in 1999 the car had less than 275kmi.

Years later (the car now has 387kmi), both the amp and the actuator still work. I suggest that you get a good rebuild and it will last years. BTW, I tend to use mine at least a couple of times per week.

My trouble is I probibly put 50K miles of actualy USE on a cruise control an average year. Something is just wrong when I have a dozen or more and not a single damn one has been functional.

I think I might take this newest amp and replace all it's IC's and transistors. There cheap enough, and the actual board is a pretty new revesion. No codeing plug though, thought that was a little odd. Who knows..

And I STILL have to do a writeup on how to use the stock control stalk with an aftermarket unit. Maybe this weekend..

But would you sell one at a good price
 

I'd love to have a spare amp around the garage, but don't want to spend a fortune...

What would you sell one of the non-working ones that isn't fried for??

PM me if you would consider it.

Re: But would you sell one at a good price
 

I usually give about $5 for a "might work, might not". Do you have a year preference? :D