This is the diagram for our ASD Relay:



I'm getting +12 to pins 30, 86, and 85. Doesn't this mean that I should see +12 on pin 87 if the relay is active?

 

Pins 85/86 are the pull in coil. One side should have power. The other side is a ground. In this case the ground is controlled by the PCM.

30 is power in for the circuit the relay controlls

87 should be hot if the coil has pulled in.

 

If the truck is OFF when you measure the voltage those readings are correct.
As Philip said above 'the ground is controlled by the PCM' and if the PCM doesn't put out ground - like when the truck is off - then you'll see the 12V on both sides of the coil.

 

Interesting. The power to the coil must be supplied from the ignition, because when the ignition is off I only see +12 on pin 30. However, when the truck is running I see +12 on both sides of the coil, which must mean the PCM isn't supplying ground.

Does anyone know what conditions will cause the PCM to shut down the ASD relay aside from the crank sensor?

 

Blown fusible link....
The white one on my truck

Just under the hood coil spring. INSIDE the loom - unless someone's been there before you.
Find the white link - looks like heat shrink tubing - GENTLY pull the wires on either side. IF the is good you'll feel resistance if the link is blown you'll feel the give it. Mine also had a nasty looking black burn on the white sleeve - pretty much a guarantee the link is blown....

I just trimmed back the white cover and used a couple of strands of 16ga wire to wrap the two ends together - after sliding a piece of heat shring over one end. Wrapped the wire tight using long nose pliers, then slid the heat shring in place and lit a match to it - carefully.
No problem for the past 6 - 8 mos.

 

But now you dont have any fuse protection at all something else will burn some where.

 

The PCM has to see a signal from the CPS before it will ground the pull in coil.

 

Good call philip I never thought of that.