Had my cruise control go south on me, turned out to be a broken (rotted) plastic vacume line under the driver's battery box.

Had to (of course) remove the battery and tray to get to it. While doing so, I noticed a small round sensor??? fixed to the battery tray with two wires coming out of it. What the heck is it? What's it for? Is there one under the passenger side battery?

BTW, if your cruise goes out, and the light on the steering wheel still functions, then probably the vacume line is cracked and leaking.

Now that the vacume line is replaced, the cruise control works to good. When pushing the set button, the truck accelerates another 10 mph or so. I need to press the coast or decel button numerous time before getting it "set" to the speed I want. Cable looks good at the pump linkage/connection point. It worked great before hose gave way. Any ideas? Thanks, Kevin

 

Battery heat sensor, these trucks charge so well that some batterys have cooked in the trays. They put that sensor on to keep from cooking the battery

 

So the sensor detects the temp of the battery, when to warm it (the computer), cuts down the charge rate?? Pretty slick. Thanks, Kevin

BTW anybody got any ideas about the cruise control having a mind of it's own?

 

Try to clean the wire connections, if that doesn't do it a new control box is only $35 from Dodge. I know this b/c I filled my box full of water when I got stuck at the Ranch :-

 

Mine does that overspeed thing on the cruise too. I notice it is worse when the temps are below 40 degrees, and it is worse when I have the PM3 setting real low or off. I assume the latter is because the engine is not as responsive/powerful without the PM3 and the computer overcompensates. Usually it will go up to 10 mph over and then settle back down after about 30 seconds. It sucks because during that 30 seconds is the time you you're gonna go through a speed trap. >

Chris