Intermittent Cruise Control

[DOCJBK]

Can anyone give some advice on how to diagnose and correct an intermittnet cruise control. I have a 560 SL with the electric tempomat control. I washed the engine compartment and the cruise started working but stopped once it dried out. Just bought the care 2 weeks ago and trying to work the small bugs out of it.

[GermanStar]

The weakest link in the chain is the cruise control amplifier.

[Mike Miller]

I have a '92 500 SL and even though our cars are different and many will commenty on the different components. My cruise also works when it is damp or the engine is still cold. It has got to be something on top of the engine. Some electrical connector for a signal that needs cleaning or something. I haven't found it yet, but I know that has to be where the culprit lies. Many good intentioned pals in the forum have pointed me to the amplifier and other expensive components, but I am not convinced.

I will be very anxious to hear if you find something. I will also let you know if I eventually find my problem.

[tecqboy]

I am NOT familiar with either your car or your CC amplifier. So, why am I answering? It has been my experiences ( over 35 years ) that when stuff works wet, but fails dry, it can often be traced to a bad ground connection. The srcews which actually hold down the components of a system to the car frame get rusty or corroded over time and dry contact resistance goes up. Get it wet and resistance drops. So, I'd try unscrewing and then re-installing the physical electrical modules of the CC system. Also, check the condition of the heavy ground cable which runs between the engine itself and the auto frame. Check the condition of the negitive battery cable where it is screwed to the body / frame. When I remount electronic modules to a frame I use stainless steel screws.

[DOCJBK]

Thanks for the input, I checked the pin connector and all the wires seem to be tight, I have not checked the ground, but I will.

[Mike Miller]

Originally Posted by tecqboy

I am NOT familiar with either your car or your CC amplifier. So, why am I answering? It has been my experiences ( over 35 years ) that when stuff works wet, but fails dry, it can often be traced to a bad ground connection. The srcews which actually hold down the components of a system to the car frame get rusty or corroded over time and dry contact resistance goes up. Get it wet and resistance drops. So, I'd try unscrewing and then re-installing the physical electrical modules of the CC system. Also, check the condition of the heavy ground cable which runs between the engine itself and the auto frame. Check the condition of the negitive battery cable where it is screwed to the body / frame. When I remount electronic modules to a frame I use stainless steel screws.

Sound advice, tecqboy. I will investigate the "grounds". It could be the gardener, with the axe, in the garden, who is my culpret! (Sorry, I couldn't help myself. I really am going after the ground points.)

[tecqboy]

It's almost always the butler, in the liberary, with the candle stick.