ML320 Cruise Control broken after engine replacement

[genustri]

Alright, the cruise control my 1999 ML320 does not work, and I am stumped. So, last year I replaced the engine in my ML (with an identical engine from an E class) because the old one was burning tons of oil. I didn't replace anything electronic on the car, just the engine. I kept the same throttle body and various other engine 'attachments'. After I got done with the swap, the CC just didn't work. Everything else was ok, and the car ran like new...just no CC. I checked all of the fuses, which were fine. Then, frustrated, i finally took it into the local MB dealership to have them diagnose the problem. They said it was the stalk switch on the steering wheel (part #0075457124) because they weren't getting a signal from it. So I replaced the switch with a brand new one and still no dice. I did some forum reading and decided to replace the brake switch, also no luck. There are no lights on, except the check engine light for codes P0141 and P0136. I called the guy at the dealership this morning and told him the switch didn't fix anything, and he said it must be something "down the line". Does anyone have any idea what could be wrong with my CC? What could a total engine replacement do to deactivate it? Are there any CC diagrams I could look at?

I appreciate any help...I feel like ripping the hair I already don't have out!

[43sqd]

Turn the key to pos. #2 and with a test light or volt meter, check to see that there is power on both contacts of fuse #22. If so................

Remove the plastic covers on the steering column (only steps 4-6 in the pdf) and access the 8 wire connector to the C/C Switch. Turn the key to pos. #2, and check to see you are getting power at the #8 BLUE wire (which comes directly from fuse #22). Then check to see that the #1 BROWN wire is ground.

[genustri]

What do you mean, or how should I check that the #1 brown wire is ground?

[43sqd]

Your question should have been worded as follows:

Thank-you for the information, but what do you mean, or how should I check that the #1 brown wire is ground?

By using a volt/ohm meter and checking for continuity to body ground. If you do not know what this is all about then Google it.

[DrX]

Originally Posted by genustri

... i finally took it into the local MB dealership to have them diagnose the problem. They said it was the stalk switch on the steering wheel (part #0075457124) because they weren't getting a signal from it. So I replaced the switch with a brand new one and still no dice. ... I called the guy at the dealership this morning and told him the switch didn't fix anything, and he said it must be something "down the line".

If you have already paid the dealer for diagnosis, you should return there and have them fix it. They won't be able to charge you again because they were wrong the first time. I can safely assume that you didn't have the dealer fit the new stalk switch - they would have done a test drive to check they'd fixed it. (And finding they hadn't, re-installed your old stalk and not charged you for it.)

Sometimes you save money by DIYing, but sometimes it's a false economy because of the money wasted on replacing parts that weren't faulty. When the dealer makes the mistake, you'd have to get a credit for it.

[genustri]

Thank-you for the information

43sqd, I most certainly appreciate and thank you for the information you've given. I'm definitely not entitled to it, just forgot to say so in my quick reply.
I checked the voltage across the fuse contacts and pretty much got a full 12V. Next I took the switch apart and tested the #1 blue wire against the car frame as well as using the #8 brown wire as the ground and both readings were at 12V as well.



DrX, thanks....yeah you're right; I just had the dealer diagnose and then replaced the switch myself. When it didn't work, I took the switch back to the dealer. Thankfully it hasn't cost anything except the diagnosis. Unfortunately I can't take it back to the dealer right now, because he is in MO and I'm in FL. Originally he said they weren't receiving a signal from the switch, and that I'd need to replace the whole combination switch. I looked at the parts diagram and then unfastened the CC switch from the combi switch and then told them it was seperate. The parts guy then told me "oh, well it looks like there is some confusion about it in our notes." I have nothing against the dealership, but I am just not close to there right now.

[43sqd]

Originally Posted by genustri

Thankfully it hasn't cost anything except the diagnosis.

Hopefully they gave you a bill. Look at it closely and see if you see P0565 written anywhere. The CEL will not illuminate with this code.

Also, the ECM controls the Throttle Actuator for Cruise Control. Maybe there is damage at the connector. And are you absolutely sure that your Throttle Actuator was transferred to the new engine.