Cruise Control Amplifier Diagnostics & Amplifier Repair - Page 2 - PeachParts Mercedes-Benz Forum

JamesDean · #16 10-19-2012, 11:49 PM

So today I received a ProgRama rebuilt cruise control unit as part of a trade. I was very curious as to what exactly they did. ProgRama is one of the big repair companies that Ive seen listed on parts websites, they also do climate control units and whatnot.

Below is some photo comparisons. The ProgRama unit was originally an 002 545 32 32 unit. They re-labeled it as an 002 545 91 32. I've taken pics of: an original untouched 002 545 32 32, the ProgRama 002 545 32 32 and one of my repaired 002 545 32 32.

Here they are for your viewing pleasure. I'll note the difference at the bottom of the post.

ORIGINAL UNIT:

PROGRAMA UNIT:

ONE OF MINE:

It looks like one of the output transistors went out on the ProGrama unit. Its pretty easy to see the blackened spot on the one pair. It'll be interesting to see how it repairs up. Those will probably end up being replaced. You can also see that they did not replace all the electrolytic capacitors. The four axial type at the front are original. You can also see they did not use any protective coating on the solder side of the board. Everything else looks original. They did re-solder the back side of the unit, mostly. You can see a lot of flux from the solder all over the place.

Its interesting to see how the word rebuilt is thrown around.

RF_126 · #17 10-25-2012, 09:21 PM

I very much enjoy your threads. The electronic control units on these mid-80s cars are, in my opinion, one of the few genuine weak spots. Finding ways to repair them without being ripped off by "rebuilders" is a godsend.

In the case of cruise control, I wouldn't normally care because I hate the whole idea of having the responsibility of driving taken away from me. I feel profoundly uncomfortable using it and have, consequently, taken the system off both my 126 cars. Colin Chapman would be proud: I simplified and added lightness.

Having said that, however, I have been testing the two old actuators I removed. One (that was never used by me at all) seems to pass the tests; the other exhibits a rather high current draw (240mA one way, 260mA the other). The motors and solenoids check out otherwise. My remaining area of concern is the potentiometer that gives feedback to the amplifier on the position of the motor/armature. Do you have any idea what the spec should be for that? On one unit, triggering the solenoid changes the resistance across pins 2 and 3 quite a bit; on the other, the resistance never changes no matter what. GDL's website is mute on that subject, but it seems to me that a complete test should look at all functions.

Thanks again for your contributions here.

JamesDean · #18 12-03-2012, 10:14 AM

RF_126 I'll look more into this when I get home tonight or possibly tomorrow. I am not sure what the expected values are to be. I would not use that high current draw unit.

In another matter:

For those of you driving cable driven speedometer cars (124,123,201/etc):

If you have bounce in your needle it can cause the cruise control to surge. My 300D 2.5's speedometer needle would occasionally bounce by about 5 MPH, so it would look like I was doing anything from 60-65 MPH. This caused my cruise control to jerk the car around quite a bit. Even with my freshly repaired amplifier and good actuator from my 300SD the cruise was only steady on cold days when the needle was mostly steady.

This past weekend I replaced the cable with a new one from MB ($102 after shipping, $87 for the part) and my cruise and needle are both ROCK steady. Well worth the money.

Just a heads up. Needle bounce can influence cruise performance.

JamesDean · #19 05-08-2013, 12:38 PM

Bump! For new members!

Billyw124 · #20 05-29-2013, 06:43 PM

This thread is exactly what i need!!

what a genius James! I'm going to read this thread through properly to see if i can find the fault.

I retro fitted cruise to my 124 coupe, I know the actuator works, and the loom is brand new. The only possible things could be the stalk, the Amp, or speed sensor behind clock.

Nothing happens when i try to engage the stalk for cruise. The first day i tried it, the car accelerated when the stalk was lifted upwards, then tried to do it again and has been dead ever since -nothing.

tried replacing the black plug at the back of the amp as i have a brand new one, still aint nothing!

JamesDean · #21 05-29-2013, 11:18 PM

Hey Billy!

I would bet that its the amplifier, especially since it sort-of worked the first day and then never again.

I dont think I've ever seen a failed coding plug before. I know some websites indicate that it fails more than the amps but in 200 amps..I've not seen it.

What 124 are we talking about here?

Sounds like an 005 545 05 32 or 014, 016 or 023 type unit. Let me know which!

If you want, you can send me an email and we can discuss the specifics there, JamesDean59@gmail.com

Billyw124 · #22 05-30-2013, 04:44 AM

Thanks mate, i have a good feeling that you'll be able to get me cruising again!

I've recently completed an engine conversion m111 220 to m104 320. yes - over here in the UK we have a 4 pot version for the 124 which i should add is a wonderful unit

however needed a bit more oooomph!

Lets however disregard the engine swap as it doesn't hold any bearing on the issue with our cruise issue. Its hooked up independently. (The M104 engine i swapped out for didn't have cruise to begin with so no fancy electronic cruise throttle body nor the fancy VDO unit in the passenger footwell!

I'll need to double check the part number on the unit but i'm sure your expert eyes will be able to figure out its either or from the below pic of my components prior to retro fitting to the car. The part numbers you mention sounds familiar + the blue rear where the pins are on the amp might help distinguish?

If you have an amp knocking about i'd be inclined to swap it out with one of your fixed units to be honest, what do you reckon?

If you need any further info let me know bud and thanks for your help!

Billyw124 · #23 05-30-2013, 05:22 AM

I believe the part number on my amp is 0145454032

Got it from digging up a few old emails i have but I will need to double check this on the actual unit.

JamesDean · #24 05-30-2013, 08:41 AM

Billy,

You are in luck I do have an 014 545 40 32 unit. The 016 and 023 units require that you remove one of the ground pins on the 14 pin connector. I believe they require you to disconnect pin 12 so that ground is only coming in on pin 14 or maybe its the other way around. I cannot remember off the top of my head.

When you performed the swap did you swap in the m104 engine + transmission or did you mate the m104 to the m111's transmission? I know that the speed signal originates in the tail shaft of the transmission and that is sent to the cluster via mechanical cable. That is then converted via sensor at the back to the cluster and that signal is sent out to the various devices.

What year/model was the donor car? What part number coding plug are you using?

Its most likely that the 014 is just tired and in need of repair.

Billyw124 · #25 05-30-2013, 09:14 AM

Fantastic, is the unit available for me to gladly take off your hands?

Yes i swapped out the engine and the gear box form the M104 to match each other. The donor car was a 1993 w124.....

diesellover 92 · #26 03-28-2017, 10:47 PM

So my cruise control just stopped working on my 92 300d. I have used it a handful of times until today. All linkage is intact and moving.

tinypanzer · #27 03-30-2017, 08:48 PM

Quote:

Originally Posted by JamesDean

Cold Solder Joints
The second problem comes from cold solder joints. Solder connects all the points on the board. I've been told that solder can have a life span of about 20 years or so before it starts to show signs of failure like cold solder joints. The cruise control boards are partially coated with a special type of polyurethane coating. This helps prevent moisture and other outside elements from oxidizing and corroding solder points. Several boards I've worked on have failed to come back to life after a simple capacitor replacement. They needed a full-on resolder of every point on the board to come back to life.

Obviously you know a great deal more about cruise control amps than I do, however I just want to point out one minor inaccuracy. The term 'cold solder joint' refers to a solder joint that was made with the solder not reaching the appropriate temperature. On lead based solders, this is pretty obvious as the joint will be dull and pitted rather than shiny and smooth. The failure I see on MB module solder joints is not this type of failure, it's a stress related failure on otherwise good solder joints which is caused by both vibration as well as thermal expansion/contraction. The result is more or less the same, but not the cause. Even a perfectly formed solder joint will crack and fail if subjected to enough stress. That is the failure mode I see most often in MB modules. I have never encountered an actual 'cold solder joint' in one.

Most often I see cracks forming around the base of the solder joint, typically where a large pin (usually the module's header pins) pass through the circuit board. Sometimes these can be hard to see, but reveal themselves when you flex or move the board or pins and the gap suddenly appears before your eyes.

I point this out because when looking for a cold solder joint you are looking for something that looks completely different than a cracked solder joint.

ah-kay · #28 04-04-2017, 04:54 PM

Pulled a 190E cruise amp from JY and it does not work. I normally pull 190E cruise amp as it is very easy to access ( in front of passenger side carpet ) and a lot of the time works good. I find the 190E cruise amp will work with 300SDL and W124 300D. Have not tried the W123 300D but I would expect it will work too.

I replaced the 2 x 22uF capacitors as circled in picture and it works like new. What I find is that an intermittent unit is hard to fix as it is probably due to dry solder joints. Difficult to locate and hard to prove. This one is completely dead and the culprit is the 2 capacitors. Hope this help the motivated DIY guys.

1991sl · #29 06-09-2017, 12:04 PM

Hi, I have a 1991 300sl will not reset to a lower speed setting after tapping the brakes to disengage. When I attempt to reset, the engine accelerates and returns to the original setting when engaged. Any thoughts? By the way; this issue seems to have developed after replacing brake pads and rotors.

hschickel · #30 03-31-2022, 11:42 PM

Is this thread still live? If so I'd love to swap an 82 300sd actuator.

Thanks