How many airbag sensors, one or two? 2004 2500HD

I'm in the process of diagnosing why it says "Service Airbag" on my odometer spot. So far, I'm getting good info regarding on what to look for and where to look. In all the research that I've done, everyone has mentioned that there are two (2) airbag sensors that are located on the frame, underneath the radiator. I only see one (1) sensor located on the frame, which is directly in the middle under the radiator. Is there a hidden sensor? Or should I be looking somewhere else? Is it possible that my truck only has one sensor?

2004 Chevy Silverado 2500HD Extended Cab 6.0 4x4

Thank you.

There are usually two front impact sensors, a left and right, both under the radiator , bolted from underneath. What code is stored? There are several other possibilities that can cause this message. Have the SIR codes checked before repairs are attempted. There are also saftey precautions that need to be taken when working on the SIR system!!!! Don't just start poking and prodding around as bad things can happen!!!!

Thank you for your safety concerns. I've been doing my best to not just poke and prod, cuz normally I would, however, I found it kinda unusual that everyone has mentioned two sensors under the radiator, and I only see one.

I have checked it with my scanner and it doesn't give me any codes. I probably need an expensive scanner.

I'm planning on checking the resistance on the sensor. According to my research, there should be some kind of resistance. And I plan on checking the module that is located under the driver seat. The grounds appear to be good also.

You really shouldn't be messing with this system if you don't really know what you are doing......you need a scan tool capable of reading SIR codes and data(most scan tools can't do this)....you need schematics.....you need trouble trees....not knowing what the code is, you have no direction to go in....

Unless a visual inspection turns up something, there is not much that you can do.....