oven temperature only goes to 275 degrees even when set higher; broiler works

I watched the video, which was very helpful...the temperature sensor was hard to pull through the small opening in the upper back left oven corner. On the back wall of the oven was a large removable circle, so I unscrewed that piece and was able to gain access to the wires attached to the temperature sensor and push it through the small opening. I used one of the new connectors, pushed it back through the small opening, screwed it back onto the oven wall, replaced the circle opening and tried the oven again...unfortunately, there was no improvement in oven temperature! My JennAir wall oven is about 17 years old, and I thought I would try this $30 repair prior to purchasing a new wall oven, but it looks like I will have to do some overtime and buy a new oven. Any other suggestions would be welcome.