Where is temp gauge located on 2004 silverado

Pull the IP and unplug it, plug it back in. When everything goes at the same time it is usually a bad connection at the plug. Also check ground wires. The can be on the steering column or behind the kick panel to the left. By the E brake. The key FOB is a different area. But can be related to the grounds.

There is a blower control resistor (manual system) or a blower transistor (automatic temp system) located behind the glove compartment in the HVAC box and this is a high failure item.

To review, you have two temp sensors, one for the gauge on the dash and one for the computer. If you unplug the sensor for the computer the reading will be minus 30 degrees or over 300 which will make it very hard to start. Unplugging the sensor for the gauge would have no effect on the computer.
According to the wiring diagram, the wire for the temp gauge is green, and the wires for the temp sensor for the computer are yellow and black.

change plugs, air filter if dirty, change fuel filter, check and replace spark plug boots if bad on coil over plug, to do this you have to check resistance of the boot. if has wires check plug wires.

It sounds to me like the gauge is working correctly. You probably have an engine that is running cold. I think I would try replacing the thermostat. Also make sure your coolant level is correct. The gauge will not work correctly if it is low.

Wire or sensor is shorted. Unplug the sensor and see if the gauge stays low, if so replace sensor. If not, find short in the wire.

bad ground on car body

it has to be either a broken gauge, faulty wiring, or poor coolant flow (although in the summer i doubt the coolant is staying 'too cold' in reality).
First, we will check the temp sensor 1. Pull the temp sensor out and let it hang. 2. Boil water -- it will be at 212* at its boiling point but cooling rapidly, so speed is key. Or better yet, if you have a thermometer and vegetable oil and steady hands, heat that up to 250* 3. Take the water or oil to the sensor and pop the sensor in it. Watch the gauge to see if it reads accurately (should show around 200 if you moved quickly with the water, oil will still be ~240ish and will work better, but is more dangerous). If the gauge is off, then we've found the problem. For better measure, if you have a thermometer you can place that next to the temp sensor to compare results.
if the temp reading is too low (lower than what your thermometer reads), it is also possible that you have a short in the wiring or simply corroded wires connected to it, adding resistance to the wire which would result in a lower reading. (people sometimes use this to their advantage with the air temp sensor -- add a 100ohm or so resistor in-line with the sensor to trick the cpu into thinking the temp is colder, prompting it to adjust the air/gas mix and yielding a couple hp increase, although damaging to your system.)
the more i think about it, the more a faulty wiring feels like it could be the problem. if the temperature is reading accurately, i'd take a serious look at the flow of coolant through the system. if it isn't heating up then it must not be contacting enough heat. there may be blockage somewhere; crimped hose or maybe just mystery gunk.
hopefully this helps, if anything it's a start. most of the time it seems like solutions are found unexpectedly when testing completely different things. good luck!

The 2002- 2007 Dodge Ram 1500 4.7 L. has a single core radiator with flat fins that become easily plugged with scale and other stuff floating around in your motors cooling system. Since these fins are so small about .040 of an inch good luck flushing out any clogged particles by doing a flush. Many of the online part stores have replacement radiators for less than $120.00 (Rock Auto, for example). Replace the radiator with a new unit. Make sure to flush the engine block and heater core before connecting back to new radiator. I completed this job over the past weekend in less than 3.0 hours start to finish. Have less than $220.00 in all hoses, Thermostat, Radiator and new coolant.

Try replacing the coolant temperature sensor for the injection system.