99 SLS with 135k miles: After driving about 30 minutes in light traffic, I noticed the voltage on the DIC was 13.9; normal for the car is 14.2-14.5. As this car has the thermistor on the battery, I pulled up the rear seat when I got home to see if the battery was hot. The battery felt OK but the cover to the under seat fuse block was very hot and must have been affecting the thermistor. Removing the fuse block cover I found about a half dozen of the relays were too hot to keep a finger on. Only code is a 1343 for Inlet Air Door Movement fault; I have had this code for a few years(tried to change the actuator but couldn't get the back screw out; A/C works fine). Any suggestions? Thanks in advance.