plugged voltmeter into both sensors (original and borrowed) and show infinite resistance. Touched to metal, still infinite resistance... Bad sensor? I don't know how I read 1.9 ohms last night...

 

Sensors are just signal generators.

On the gas engines, C1 pin 8 is crank position sensor signal wire. Speedometer signal is C2 pin 27. White wire with orange trace.

 

The RAWL sensor is a magnetic proximity switch. Pulses generated asn stell moves in front of it and then away. Ohms will not tell you if it is working. Got to see if you can simulate the tooth moving past it.

On an earlioer post (previous page) it is not clear to me what you are reading.

 

I don't know anymore. I found another thread that said his CAD wasn't grounded. I jumped a ground to it and the ABS light went out, but I still had no speedometer. Now the light's come back on. I think it's grounded by the drivers headlight. I'm gonna clean them up (they were loose by the way) and see. Now, I have almost 5 volts to the RWAL sensor. Still no signal. Bummer. So, you need like an oscilloscope to read the signal, right? What now?

 

Put the rear up on jackstands, and backprobe c2 pin 27. (with everything hooked up) Put the truck in gear, and have someone vary speed a bit, see what signal you get there.

 

What am I looking for? I have a crappy analog and decent digital voltmeter. Am I looking for a consistent voltage, or a sine wave? BTW, I had like 1 volt to the RWAL sensor before

 

You wanna know something weird? C2, pin 27 is EMPTY. Yep, thats right. I counted 11 times and read the little numbers molded into the end. The white/orange wire in in pin 26. Weird, right? But I cleaned the grounds and the ABS light is out. Still no speedo. Now what? I'm gonna call it a night. I want to make sure the 12th time in the daylight before I move that wire over.

 

I took a wood bit and chucked it in drill press. Turned it on slow speed and put sensor about 1/8" away and counted pulses to confirm that RAWL sensor was working. Obvious hazard - rotating bit. I clamped sensor in small machine vice. be careful.

 

Okay, in the daylight, I can see better. It's in the right slot, Pin 27. Called the dealership, got a new RWAL sensor coming. Will be here tomorrow. Gonna install it and rule that out.

 

Good call.