Intellitec and rear furnace

Take PC compressed air can and blow out the Intellitec wall control. After 22 years, dirt and dust may have built up enough to cause contac problems on the slider. Furnace problems are usually 99 percent on the furnace and its controls, not the aftermarket wall tstat and control. I would also blow out the furnace controls and ignition module for the same reason. Dirt and dust build up can cause intermittent contac problems. If this does not fix it, then I would suspect a dirty internal sail switch problem. Since one the sail switch attempts to make a good contac and then the furnace fails (switch opens) then runs on and off all night until a long rest before the next night. Doug