I'm betting actuator.

The amp has an inclination to "let go" of cruise when digital or analog conditions aren't right.

If the feedback potentiometer in the actuator is sketchy (drops signal, skips across dead spots, etc), or the actuator motor drive is not getting the lever to its intended position, the the amp reads these things as "not right" and drops cruise.

Lube up the mechanisms on the actuator first, see if something is binding. That would be the first step, especially if a "bumpy road" is causing the drop.

Of course the amp itself can have a poor solder joint or connection pin. Which over a bump would cause same thing, so it could be amp. Or for that matter, connector at the actuator. Ensure the actuator connector is not loose / frayed / dirty / etc.

__________________
Cheers!
Scott McPhee

1987 300D

All good suggestions. I can check 1) if the stalk plug is connected (well...removing the steering wheel only...I hope) 2) I can check the actuator- take it out and inspect (not sure if I need to take the intake off for that...hopefully not and 3) amplifier reman..which costs some money.
I 'll check 1) and will do 2) and then see what happens.

update:
I had my amplifier remanufactured ( I know a good address/nice person who can reman the unit for less than the other companies) , also I changed the
stalk. It seem to work now properly.
So the problem was not the actuator!

Martin

Glad things are working well. However, an actuator problem is not necessarily ruled out in that you don't yet know whether the original amp failure was caused by the actuator....but time will tell. (Although you could ask the guy who did the rebuild whether he noticed any damage to the output transistors.) In my case, my rebuilt amp lasted for three weeks or so and then died. Subsequent research verified that the actuator was the problem. The longer you go without a problem, the more confident you can be the your actuator is OK.

Not trying to rain on your parade....just trying to help people learn (and save money) from my mistakes.

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 179k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 77k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Thanks for the parade notice.
I asked the person who was redoing my amplifier and he said the transistors were fine.He exchanged them anyway but he thinks the actuator is doing fine from what he could tell.
If someone is interested. The person remanufacturing these kind of parts is James Duncan. PM me and I will put you in contact.

That's excellent. If the output transistors were fine, you should be in good shape. As I understand it from Peter at GDL, if the actuator is the culprit it will be evidence in blown output transistors because the actuator is drawing too much current.

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 179k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 77k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife