May have to take the car to a certified speedometer repair shop
dirt in the speed snsor bad speedo head in the dash
I don't think speedo make heads
There are two coolant temperature sensors. One is located near the water pump and the other on the head above the starter.
No. The speed sensor is located on the transmission, and is what drives the speedometer cable, which drives the speedo head. The speedo head is another name for the the speedometer, which is the display gauge that you see while sitting in the car.
Replace the speedo head assembly. It is a sealed unit, with no servicable parts. If the speedometer is working, then the cable and the speedo drive gears are working. The failure must be inside of the speedo head assembly itself.
There are several torx head screws around the rim of the lens. If it just one of the bulbs that needs changed and the screw heads are stripped, you can get to the bulbs by reaching under the tail fin and into the back of the light.
The 2005 Cadillac CTS has 36.9 in. of rear head room.
The 2013 Cadillac Escalade has 41.1 in. of front head room.
The 2009 Cadillac CTS has 38.8 in. of front head room.
The 2014 Cadillac Escalade has 41.1 in. of front head room.
The 2006 Cadillac CTS has 38.9 in. of front head room.
The 2010 Cadillac SRX has 38.4 in. of rear head room.