I believe multi-meter is the other tool mentioned above.
You might not have time or cash, but the Tech 2 can potentially save a lot of money. More than the $300 cost... More importantly, saving time. And time is money, especially for those of us with daily drivers needed to get to work.
The real beauty of the Tech 2 is that it can get into virtually every sensor and control device on the truck. Being able to look at a specific part, seeing what its current status is (on/off/idle/open/closed) and live data on things like voltage into and coming out of the device, is HUGE! It can speed up the process of identifying which things are working and not working. The real cool part is being able to go in and manipulate all these components, make them open/close/on/off and see if they are receiving and sending current like they should. All that information, without crawling under or even disconnecting any wire connectors.
I had a Service Airbag light come on just yesterday. I got in to see that I have an issue with my front impact sensor performance. I will be checking to see if it is just a crusty connection. If not, I'll replace the sensor. Since this was only my second time plugging the Tech 2 into my Tahoe, I decided to poke around and check out control functions under the different "Special Functions" menus. Through the Tech 2, I was rolling windows up and down, locking/unlocking doors, recalibrated the temperature control door actuator. It was fun!
Not harping on you for not having one. Just letting you know the power of information and what kind of information the Tech 2 can give you in diagnosing problems.
Like
@rockola1971 mentioned, maybe somebody near you might have a Tech 2 nearby and may even be willing to help you out.