I've got "Fiona" torn down for a major tune up. Fiona is a '96 Ram 1500 4X4. About 150K on the engine. The speedometer reads high and is showing 164K, but at 40 mph, it reads 45. At 72 mph it reads 80. I'll be replacing or repairing a bunch of cracked vacuum hoses and line, new cap and rotor, plugs, plug wires, plenum repair (that's why it's torn down) timing chain, all the hoses (bypass was swollen and about to fail) and general clean up.

Now, my question. One of the coolant sensors had a crack and broke when I unplugged it. Which sensor does what? There's a black one and a white one. The white one broke. I've got another black one but the white one is unavailable locally right now. I'm assuming one is for the temp gauge and the other for the computer open loop reading.

 

One wire sensor is for the gauge, two wire sensor is for the pcm.

 

Thanks, that's what I needed to know. I'm not a fan of compooters.