My auxiliary pump wasn't running during or after I shut down the car. This is like a turbo timer for those who don't know, it runs water through the turbo for some time interval after shutdown to prolong the life. It's located on the passenter side above the electric fan. They are only $100 and very easy to replace.

I tried to read the voltage going to mine, but you can't because the controller senses that there isn't a load and stops sending voltage when it senses an open. Although, with a voltmeter, you can see it send voltage about once every 15 seconds or so, then back to zero. I just replaced mine and it works great.

You can tell if yours is working by turning on the car, it should run continuously. Grab the hose that exits the top and you should feel water pulsating. It's pretty easy to feel so if you think you don't, you probably don't. Also, after reaching operating temp, then shutting off the car causes it to run for a while too, this is easier to tell if it's running.