You are right on with the things that control weather or not you have boost. It sounds like the first thing you should do is make sure the IC lines are purged and you have power right at the IC pump. Clutch failure is not common. It sounds like it is not engaging like you said and if you can't check IAT's (cheap scan gauges for $30-$50) then you may have to do it the ol fashion way. See if the IC pump is really pushing coolant, start the car, drive it (has to be in a drive gear) up to about 2,500 RPM, park it and leave it running, pull a coolant hose off the outlet IC pump side to see if coolant is flowing (instead of getting under the car pull the return coolant line off from above for less mess). I was able to avoid this by listening to and feeling that my pump was working even while the engine was running but it needs to be on ramps/jackstands.