Pulp Fiction (aka Reefer Madness)

Get a digital meat thermometer, the kind with a probe (looks like a short knitting needle with a small box on the end). You can actually even find them in most truckstops. It will give you a fairly accurate reading, and do it quickly.

The best way really depends on the produce, I usually hauled lettuce (out of Salinas) so I basically had to temp death by stopping the loaders on forklifts so I could get a pulp temp. You do this by shoving the probe into the thickest part of the lettuce head (or bunch, if its romaine) and see what you got. And even after being run through the quick-chiller (think giant, liquid Nitrogen powered freezer) sometimes the temp is too high (since the produce is usually loaded right after picking).

Good luck with your reefer madness, just hope you don't get a load that's too warm, your reefer will run wide-open, then defrost 'cause the cooling coils are frozen. After 2 days of this, it will finally be in the normal temp range.

 

Awesome, your trainer sounds like he's got it all together. When you get your own truck, you will get a feel for how much fuel the reefer burns, (which is also dependent upon what you're hauling) and you will hoepfully never run into the same problem.
And, once you fill the reefer up, you have to open the front panel and build the reefer motor's prime back up otherwise it ain't gonna start (as you two surely found out).

Goodluck with that trainer, keep us posted!