Replace the cruise control amplifier on W126 S-class Benz cars

[@steviewaichulis]

Great video. Thanks!!

[@straybenzes]

All the best and thanks!

[@ImpalamansGarage]

Thanks for the tips. About to start this job.

[@straybenzes]

Good luck!

[@Rasulovification]

Thank You for your great videos and explanations!

[@straybenzes]

Thanks!

[@sas8403]

If the ABS light is on will it stop the cruise control from working

[@straybenzes]

Nope

[@youtoobe169]

Thanks for posting this! Do the code plugs go bad? I was able to find the amplifier, but not the code plug. I will have to reuse the code plug.

[@straybenzes]

I am going to be careful here, but overall the code plugs typically are not the issue. Usually people will forget to make sure that they are using the correct one for their car. Good luck.

[@youtoobe169]

@@straybenzes Thanks for the tip. I am working on sourcing a rebuilt unit. If I can't find one, I did find a couple sources for genuine Mercedes units.

[@straybenzes]

@@youtoobe169 Here is one source: www.cruisecontrolrepair.com also try Kris Rose @ [e-mail] He is a great resource.

[@straybenzes]

@@youtoobe169 All the best for you.

[@youtoobe169]

@@straybenzes So, the amplifier apparently was not the problem. I have an actuator arriving today.

[@mikkelgundersen2904]

Hi! Great video! Do you know how to test if the ECU is working?

[@mikkelgundersen2904]

or amplifier :)

[@straybenzes]

@@mikkelgundersen2904 Hmm. I do not recall the ECU tying in with the cruise control. If the cruise control does not work at all or it initially works stops intermittently or drifts and then stops it is usually the amplifier. I have had pretty good luck by installing new capacitors into the amplifier, but I do not have the experience or tools diagnosing the rest of the amplifier components (other than resistors). Send a mail to Kris Rose and get yours fixed or just buy a refurbished one from him. All the best!

[@rb.867]

What is a code plug?

[@straybenzes]

That is the plug that you can see on the left side of the amplifier. Earlier generation cars did not have that, but if yours does have one, make sure that the same part number is back on any amplifier that you re-install on your car.

[@ImpalamansGarage]

What year model car is this?

[@straybenzes]

87 300SDL and 89 420SEL

[@abdullahalzoabi567]

@@straybenzes I am big fan of you and I am watching your great videos and giving you like all the time I really don’t know if you can help me or not but here is my issue below: my car is MB W126 year 1990 model 300SE and it is USA specifications. my cruise control is working for engaging and disable, but the issue is once it is engage is not stable. I mean speed will go up and down. for example if I fix the speed for 80mph the cruise will engage and the speed will goes down to 78mph then suddenly go back very sharply to 80mph and continue like that. Is the issue from the amplifier or actuator or etc. Watching you from Saudi Arabia Best wishes.

[@straybenzes]

@@abdullahalzoabi567 Thank you so much! Your amplifier is in need of repair. You can either try getting it fixed (I do not know any good source where you are located though), Most used units are not working or they are for another model. I would keep the code plug that should be used on yours. That way you can at least make sure that it will work with your car. Hopefully you will be able to find a good used or repaired unit.

[@straybenzes]

Sorry, Abraham. I saw your note but I had to delete the first video due to some editing issues. Much like a mentioned before, you may have to replace the amplifier.

[@abrahamghannam2137]

Stray Benzes 😊 thank you happy new year Ralph

[@straybenzes]

@@abrahamghannam2137 Same to you

[@rb.867]

My w126 cruise on hills goes full acceleration and scares the crap out of you

[@straybenzes]

Yeah, that amplifier needs to be repaired or replaced. It is too unsafe and at least totally impractical to drive it that way.