w140 Cruise Control Not Working
 

Took my 93 500SEL to get new tires put on last week and get a front end alignment. Now that we got the car back the cruise control doesn't work.

Is there some little cable they may have inadvertently disconnected thats keeping the cruise control from working that I can hook back up myself? Some other easy fix or troubleshoot that I can do to figure out whats wrong?

And I don't want to have to take it back to them because I wasn't very pleased with service they offered and I'd rather not have to deal with the sun-of-a-guns unless absolutely necessary.

Most likely coincidence. I do not see any connection between CC and tires/alignment. Check the fuse, brake light bulbs and connection to actuator in engine compartment. Otherwise your amplifier may have gone bad.

cruise also looks at relative speeds of wheels - if it thinks its slipping it will disengage - so its connected to the abs sensors.

but then you should have an abs fault light on as well - check it works on some nice slidey stuff (when the wife isnt watching ;) )

I played with the cruise control a bit over the last week. My wife drives the car regularly and wants the cruise control fixed.

So I took the car for a few spins and here's what I was able to see:

1) Cruise Contol works below about 40mph just fine
2) While pushing the cruise control lever to accelerate, it will accelerate all the way to around 55-60mph then quit accerating and not hold speed.
3) Pushing the lever back to accelerate after this will get a very brief acceleration (maybe 0.25-0.5s worth) but then it will not hold speed or accelerate again.

So are these all symptoms of the Cruise Control Amplifier going bad?

If it is, where is it located at and is it an easy thing to replace? Anybody by chance have a part # for it for a 93 500SEL?

Thanks again.