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

JamesDean · #1 05-19-2012, 03:03 AM

Hey everyone,

As some of you may or may not know, I've been helping people out with their cruise control systems on these 80-90s vintage cars. I figured I'd post up here too and offer as not everyone frequents the for sale/trade forum. I figured I'd also centralize everything that way there aren't a bunch of stray posts randomly spread out everywhere.

Most of the time its an amplifier that has gone south. A fairly easy and relatively in-expensive fix. However if there are some simple tests that can be done to rule out other possibilities. So post up your cruise troubles here and between the forum guru's and myself we should be able to fix you up!

I've got a small stock of fully repaired/tested amplifiers built up right now. Not all of these will be applicable to your car so in that case you'd have to send the unit to me and I'll repair it and return it to you within about a week. I've repaired just under 30 units so far and all have come back fully functional.

If you've got any questions or anything I'll be glad to help out. I can even walk you through the diagnosing if you'd like Just let me know.

Feel free to PM me or email me (jamesdean59@gmail.com) if you'd like. I'd be happy to help.

Here's the small stock I mentioned earlier:

Quote:

Current Units for Sale:

1 AVAILABLE - 002 545 16 32
201.024 - 190E 2.3
201.122 - 190D 2.2
126.120 - 300SD

SOLD OUT - 003 545 09 32
107.048 560SL
124.026 300E 2.6
124.028 300E 2.8
124.030 300E
201.028 190E 2.3
201.024 190E 2.3
201.034 190E 2.3-16

3 AVAILABLE - 005 545 05 32
IMPORTANT SEE NOTE AT BOTTOM
124.026 300E 2.6
124.030 300E 3.0
124.050 300CE
124.090 300TE
124.133 300D
124.193 300TD
126.024 300SE
126.025 300SEL
126.035 420SEL
126.037 500SEL
126.039 560SEL
126.044 500SEC
126.045 560SEC
126.134 350SDL
126.135 350SDL
140.134 300SD / S350
201.028 190E 2.3
201.029 190E 2.6
201.034 190E 2.3-16
201.126 190D 2.5
107.048 560SL

Note: The 005 unit has a plug that is on the back of it that is matched to a set of specific chassis so you'll either need to have your original plug or I might have on here that will work, just let me know what you need.

-Kris
__________________

JamesDean · #2 06-02-2012, 12:45 AM

I figured I'd update this with my current stock thats for sale, with a picture too!

Just drop me an email (jamesdean59@gmail.com) or a PM on here if you're interested!

1 SOON TO BE AVAILABLE - 001 545 76 32
126.032 - 380SE
126.033 - 380SEL
126.037 - 500SEL
126.043 - 500SEL
126.044 - 500SEC

1 AVAILABLE - 001 545 79 32
123.123 - 240D
123.153 - 300CD
123.133 - 300D
123.193 - 300TD

1 AVAILABLE - 002 545 32 32
123.123 - 240D
123.153 - 300CD
123.133 - 300D
123.193 - 300TD

2 AVAILABLE - 002 545 16 32
201.024 - 190E 2.3
201.122 - 190D 2.2
126.120 - 300SD

3 AVAILABLE - 005 545 05 32
REQUIRES CODING PLUG! I have some if you need one!
124.026 300E 2.6
124.030 300E 3.0
124.050 300CE
124.090 300TE
124.133 300D
124.193 300TD
126.024 300SE
126.025 300SEL
126.035 420SEL
126.037 500SEL
126.039 560SEL
126.044 500SEC
126.045 560SEC
126.134 350SDL
126.135 350SDL
140.134 300SD / S350
201.028 190E 2.3
201.029 190E 2.6
201.034 190E 2.3-16
201.126 190D 2.5
107.048 560SL

Air&Road · #3 06-02-2012, 05:42 PM

James,

In the course of finding that my clutch switch was my cruise control problem I bought a used CC Amp for my 88 300E. If you can use it as a core, I will send it to you no charge as long as you remember that I already sent you a core if I ever need mine fixed, then I can pay the repair cost and send you the old one again at that time.

Let me know if you need it or need any information on it.

JamesDean · #4 06-02-2012, 07:05 PM

Quote:

Originally Posted by LarryBible

James,

In the course of finding that my clutch switch was my cruise control problem I bought a used CC Amp for my 88 300E. If you can use it as a core, I will send it to you no charge as long as you remember that I already sent you a core if I ever need mine fixed, then I can pay the repair cost and send you the old one again at that time.

Let me know if you need it or need any information on it.

Larry,

Certainly, I'll mark it down in my spreadsheet next to your records! I'll drop you a PM on here with more information.

JamesDean · #5 06-03-2012, 05:49 PM

Here's my complete diagnostics for the cruise system, step by step:

STEP 1
Speedometer OK? All Brake Light bulbs in tact? Goto #2. Otherwise repair.

STEP 2
Test the cruise first on the road. Once above 30 mph, hit the cruise control stalk in the 'accel set' direction. If it tries to work, engages momentarily, then your problem is most likely the cruise amplifier, see #3. If it does not work at all see #4.

STEP 3
You can send me the amplifier to repair if you'd like. My service fee is $60 + $6 for return shipping. I might have a unit in stock for your car. If I do, once your old one arrives, the repaired one will ship out immediately. If not, I'll repair the one you sent in and have it back to you within a weeks time. As a precautionary measure, you should check out the health of your cruise control actuator, see step 5.

STEP 4
Test the signals being sent to the cruise control unit. The cruise control stalk might not be working properly or your brake disengage might not be working.

http://www.peachparts.com/shopforum/2930398-post24.html

If everything checks out go to #5, if not, you probably have to replace the cruise control stalk. I've not really seen many broken/bad ones but its always possible

STEP 5
Test the cruise control actuator and make sure the linkage is connected! As the cruise control actuator ages, it will tend to draw more current from the cruise control amplifier, there is a limit on what the amplifier can provide. Should the actuator draw past this limit then there is a good chance that eventually it will kill the amplifier.

http://www.peachparts.com/shopforum/2913150-post5.html

If this checks out, goto #6, otherwise replace the actuator with one that tests out OK and start back at #1.

STEP 6
Well, if you've tested everything that I've said the only thing left to be faulty is the cruise control amplifier. Like I said earlier, I'd be happy to repair it for you, my service charge is $60 + $6 for return shipping. If I have a unit thats compatible with yours in stock, as soon as your old unit arrives, I will ship the repaired replacement out, if not I'll fix up the one you sent in and have it back to you within a weeks time.

JamesDean · #6 06-14-2012, 07:33 PM

Another inventory update. I'll try to keep these to once every two weeks or so. Just drop me an email (jamesdean59@gmail.com) or a PM on here if you're interested!

1 AVAILABLE - 001 545 76 32
126.032 - 380SE
126.033 - 380SEL
126.037 - 500SEL
126.043 - 500SEL
126.044 - 500SEC

1 AVAILABLE - 001 545 79 32
123.123 - 240D
123.153 - 300CD
123.133 - 300D
123.193 - 300TD

2 AVAILABLE - 002 545 16 32
201.024 - 190E 2.3
201.122 - 190D 2.2
126.120 - 300SD

1 AVAILABLE - 003 545 09 32
107.048 - 560SL
124.026 - 300E 2.6
124.028 - 300E 2.8
124.030 - 300E
201.028 - 190E 2.3
201.024 - 190E 2.3
201.034 - 190E 2.3-16

4 AVAILABLE - 005 545 05 32
REQUIRES CODING PLUG! I have some if you need one!
124.026 - 300E 2.6
124.030 - 300E 3.0
124.050 - 300CE
124.090 - 300TE
124.133 - 300D
124.193 - 300TD
126.024 - 300SE
126.025 - 300SEL
126.035 - 420SEL
126.037 - 500SEL
126.039 - 560SEL
126.044 - 500SEC
126.045 - 560SEC
126.134 - 350SDL
126.135 - 350SDL
140.134 - 300SD / S350
201.028 - 190E 2.3
201.029 - 190E 2.6
201.034 - 190E 2.3-16
201.126 - 190D 2.5
107.048 - 560SL
129.061 - 300SL
129.066 - 500SL

JamesDean · #7 07-22-2012, 09:21 PM

Another inventory update. I'll try to keep these to once every two weeks or so. Just drop me an email (jamesdean59@gmail.com) or a PM on here if you're interested!

1 AVAILABLE - 001 545 76 32
126.032 - 380SE
126.033 - 380SEL
126.037 - 500SEL
126.043 - 500SEL
126.044 - 500SEC

1 AVAILABLE - 002 545 16 32
201.024 - 190E 2.3
201.122 - 190D 2.2
126.120 - 300SD

1 AVAILABLE - 003 545 09 32
107.048 - 560SL
124.026 - 300E 2.6
124.028 - 300E 2.8
124.030 - 300E
201.028 - 190E 2.3
201.024 - 190E 2.3
201.034 - 190E 2.3-16

2 AVAILABLE - 005 545 05 32
REQUIRES CODING PLUG! I have some if you need one!
124.026 - 300E 2.6
124.030 - 300E 3.0
124.050 - 300CE
124.090 - 300TE
124.133 - 300D
124.193 - 300TD
126.024 - 300SE
126.025 - 300SEL
126.035 - 420SEL
126.037 - 500SEL
126.039 - 560SEL
126.044 - 500SEC
126.045 - 560SEC
126.134 - 350SDL
126.135 - 350SDL
140.134 - 300SD / S350
201.028 - 190E 2.3
201.029 - 190E 2.6
201.034 - 190E 2.3-16
201.126 - 190D 2.5
107.048 - 560SL
129.061 - 300SL
129.066 - 500SL

Hit Man X · #8 07-23-2012, 03:48 AM

Yay, Kris repaired the unit for my SDL

polarisrmk · #9 08-01-2012, 03:47 PM

I have a faulty cruise amp from a 1987 300d. what typically goes bad in the amp? I have pulled it apart and see no obvious problems or cold solders.

JamesDean · #10 08-01-2012, 03:49 PM

Quote:

Originally Posted by polarisrmk

I have a faulty cruise amp from a 1987 300d. what typically goes bad in the amp? I have pulled it apart and see no obvious problems or cold solders.

Typically its the capacitors. I believe your model should be a 004 545 24 32 and it should have 2x 10uF radial, 1x 22uF radial, and 2x 2.2uF axial. Typically one or more of those go bad and usually a cold solder joint somewhere.

If you're up to the repair, I could mail you a set of capacitors for $5. Or I could repair the unit for you, whichever you'd like.

-Kris

ps2cho · #11 08-01-2012, 04:28 PM

My CC on the wagon has been acting funny the last few months. Sometimes it acts perfectly normal, and others its hunting to keep the speed by opening/closing the throttle really quickly over and over. Does that sound like the CCA?

JamesDean · #12 08-01-2012, 05:47 PM

Quote:

Originally Posted by ps2cho

My CC on the wagon has been acting funny the last few months. Sometimes it acts perfectly normal, and others its hunting to keep the speed by opening/closing the throttle really quickly over and over. Does that sound like the CCA?

That sounds like what my buddy's 560SEL is doing right now. You can sometimes feel it.

I do think that sounds like the CCA. Typically behaviors like you describe are directly related to the CCA.

JamesDean · #13 08-20-2012, 08:33 PM

Just thought I'd update this again. It has been a while! I've got the following available right now, if you don't see your car on the lists please feel free to email (jamesdean59@gmail.com) or PM me and I'll see what we can to do help you out!

1 AVAILABLE - 001 545 76 32
126.032 - 380SE
126.033 - 380SEL
126.037 - 500SEL
126.043 - 500SEL
126.044 - 500SEC

1 AVAILABLE - 002 545 16 32
201.024 - 190E 2.3
201.122 - 190D 2.2
126.120 - 300SD

1 AVAILABLE - 004 545 24 32
124.193 - 300TD
124.133 - 300D
201.126 - 190D 2.5

2 AVAILABLE - 005 545 05 32
REQUIRES CODING PLUG! I have some if you need one!
124.026 - 300E 2.6
124.030 - 300E 3.0
124.050 - 300CE
124.090 - 300TE
124.133 - 300D
124.193 - 300TD
126.024 - 300SE
126.025 - 300SEL
126.035 - 420SEL
126.037 - 500SEL
126.039 - 560SEL
126.044 - 500SEC
126.045 - 560SEC
126.134 - 350SDL
126.135 - 350SDL
140.134 - 300SD / S350
201.028 - 190E 2.3
201.029 - 190E 2.6
201.034 - 190E 2.3-16
201.126 - 190D 2.5
107.048 - 560SL
129.061 - 300SL
129.066 - 500SL

JamesDean · #14 08-20-2012, 08:35 PM

I came across a reply I wrote to a question posted on Benz World about the cruise control system, how it works and what goes wrong.. Figured that would be useful in this thread:

How the unit operates normally:

The amplifier receives a signal that is generated in the tail shaft of the transmission. Once you hit 'accel set' this signal is stored.

The cruise control unit engages the solenoid in the actuator and it holds the throttle linkage in place. When this signal changes to a lower frequency, the cruise module will command the actuator to move the armature forward, pulling the throttle linkage with it and thus speeding up the car. Once the amp sees the signal is back to the originally set frequency it stops advancing the arm and releases it until it returns to its previous position since the linkage is spring loaded the motor doesnt have to do this work.

What goes wrong over the years?

Capacitor Aging
On the cruise control amplifier there are several energy storage devices called capacitors. These devices store the energy needed power the circuitry, engage the solenoid, and move the armature. These devices have a limited amount of life in them when compared to the other components on the board. They have a life rated in the hours 2,000 hours @ 105C is fairly common. Other capacitors on the board are rated for 300,000 hours @ 105 C and will last probably longer than the car itself.

When you have these capacitors age, they loose their ability to hold charge and thus make it difficult to perform necessary operations like power the chips that monitor and compare speed signals. It makes it especially difficult to send current to the motor to move arm and solenoid. That's where you get most of the intermittent behavior.

I've heard some people say that the Germans also had quality problems with their capacitors. I've seen a few different brand capacitors used over the years so there might be some evidence to support this. Additionally, my one 300SD, which was purchased new in 1982 had a repair order in 1983 for a replacement cruise control amplifier. The bill would have been $450 (in today's money). My grandparents never went through with it and thus the car never had cruise really. I removed the board from the car and performed my normal repair routine. Worked perfectly.

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.

Actuator Failure
This type of failure is actually rare. I've worked on 35+ cruise control units now and none of them have had any signs of actuator failure.

The actuator has a motor and solenoid inside of it. As the motor ages and wears it will start to draw more current from the cruise control amplifier. If this current reaches a suitable high level it can cause damage to the amplifier rendering it inoperable. The output transistors--the devices responsible for supplying power to the motor--are rated up to 4 amps. The actuator should draw an maximum of 220mA or so. Anything higher, say near 250mA and you should consider sourcing a used one. Most of the actuators I've seen draw between 120-220mA. I don't see a problem with that range. Once you get rather high numbers well beyond 250mA the transistors will heat up, they'll start to draw lots of power on the circuit board, this will cause everything to heat up. Some parts of the board are not designed to handle this and they break down and well that's the end of the amplifier!

For information about testing your actuator, see my post here:
http://www.peachparts.com/shopforum/2913150-post5.html

Other Problems

Poor/Bad Speed Signal
This would be more common in 123/124/201 chassis cards with a mechanically driven speedometer. In these cars the tailshaft gear train drives a cable that reaches up to the back of the instrument cluster. This drives the speedometer. There is a small unit attached to the speedometer that converts the mechanical signal to electrical. This unit can go bad, although I've not experienced or heard of it really. I only know of the one that was in my early test bench setup that failed (largely due to my curiosity at its inner workings).

In 126 chassis cars, there is a device on the transmission that converts the mechanical movement of the gear train into electrical signal. From there a wire carries it up to a connector located just to the right of the accelerator pedal, then up into the instrument cluster and off to the cruise control unit. I've not encountered any units that have failed. Only issues with wiring at that connector next to the pedal and that was an isolated incident with my friends 560SEL (it was pretty beat up).

Low System Voltage
If the car's overall voltage falls to below 10 or so volts. The cruise control system will disable. The newer style units may work a little longer than the older ones at this lower voltage however, if you're under 10V you've got bigger fish to fry than the cruise control.

I hope this answered your questions. The short answer is really capacitors and cold solder joints. If you've got anymore questions, please feel free to ask. I'd be more than happy to answer them.

If you're interested in one of the units or a repair for one that's not listed, drop me an jamesdean59@gmail.com or drop me a PM on here.

-Kris

JamesDean · #15 10-07-2012, 02:02 PM

Here is another inventory update:

Current prices are at $60 for a unit plus shipping. $6 if you are in the US, $14 if you are in Canada. (I think) $16 if Australia, UK, most of Europe too.
Repair success rate is currently at 93%!

1 - 001 545 76 32
126 126.032 380SE M116
126 126.033 380SEL M116
126 126.037 500SEL M117
126 126.043 380SEC M116
126 126.044 500SEC M117

2 - 002 545 16 32
126 126.12 300SD OM617
201 201.024 190E 2.3 M102
201 201.122 190D 2.2 OM601

1 - 002 545 82 32
126 126.120 300SD OM617
201 201.122 190D 2.2 OM601

1 - 003 545 09 32
107 107.048 560SL M117
124 124.026 300E 2.6 M103
124 124.028 300E 2.8 M103
124 124.030 300E M103
201 201.024 190E 2.3 M102
201 201.028 190E 2.3 M102
201 201.034 190E 2.3-16 M102

1 - 003 545 86 32
123 123.193 300TD OM617
126 126.120 300SD OM617
126 126.125 300SDL OM603
201 201.122 190D 2.2 OM601
201 201.126 190D 2.5 OM602

2 - 004 545 24 32
124 124.133 300D OM603
124 124.193 300TD OM603
201 201.126 190D 2.5 OM602

2 - 005 545 05 32
107 107.048 560SL M117
124 124.026 300E 2.6 M103
124 124.030 300E 3.0 M103
124 124.050 300CE M103
124 124.090 300TE M103
124 124.128 300D 2.5 OM602
124 124.133 300D OM603
124 124.193 300TD OM603
126 126.024 300SE M103
126 126.025 300SEL M103
126 126.035 420SEL M116
126 126.037 500SEL M116
126 126.039 560SEL M117
126 126.044 500SEC M117
126 126.045 560SEC M117
126 126.134 350SD OM603
126 126.135 350SDL OM603
129 129.061 300SL M104
129 129.066 500SL M119
140 140.134 300SD / S350 OM603
201 201.028 190E 2.3 M102
201 201.029 190E 2.6 M102
201 201.034 190E 2.3-16 M102
201 201.126 190D 2.5 OM602

2 - 023 545 21 32
107 107.048 560SL M117
124 124.026 300E 2.6 M103
124 124.030 300E 3.0 M103
124 124.050 300CE M103
124 124.090 300TE M103
124 124.128 300D 2.5 OM602
124 124.133 300D OM603
124 124.193 300TD OM603
126 126.024 300SE M103
126 126.025 300SEL M103
126 126.035 420SEL M116
126 126.037 500SEL M116
126 126.039 560SEL M117
126 126.044 500SEC M117
126 126.045 560SEC M117
126 126.134 350SD OM603
126 126.135 350SDL OM603
129 129.061 300SL M104
129 129.066 500SL M119
140 140.134 300SD / S350 OM603
201 201.028 190E 2.3 M102
201 201.029 190E 2.6 M102
201 201.034 190E 2.3-16 M102
201 201.126 190D 2.5 OM602
202 202.022 C220 M111
*Note you will need to remove one pin from the 14-pin connector for this unit to work.