my spped thermonitor stopped working on my 2005 caddilac deville how can i fix it it shows eletrical sys when i start or drive the car

well, you will have to have money to fix it- this car is not one that will let you cheap out- money to pay a real mechanic and money to buy the expensive little electronic part, whatever it may be- maybe you could make some extra money by putting a patent on these great words you make up like "speed thermonitor"