How can I get the fuel gauge to start back reading after battery replacement in a 1994 Cadillac Deville after battery replacement

SOURCE: 2003 cadillac deville want start

check battery voltage, if battery voltage is ok, you may need to check fuses under hood on passengers side, if start fuse is ok, you may need to have your starter replaced

SOURCE: 1994 cadillac deville concours

On my car, which is the same as yours, it is located on the manifold top back left. Pictures in the book just show it on top.

SOURCE: what size battery does a 1994 cadillac deville

According to Optima's battery selector, you need...
Part Number: 34/78 (9004-003) RedTop®; Battery; BOXED; Group 34/78; Cold Crank Amps 800; Crank Amps 1000; Reserve Capacity 110; Ampere Hour 50; Dual Terminal; L-10 in.; W-6 7/8 in.; H-7 13/16 in.;

SOURCE: location of fuel filter cadillac deville 1994

under the vehicle driver side in the center of the car.cant miss it

SOURCE: '97 Cadllac Deville Concours reading "Anti Theft System Problem"

I had the same problem. trying to save money i took it to several auto places who thought they could fix it..... after a lot of money and my 800.00 after market alarm was taken off i had it took to the dealer . They fix it in two hours they put in new switch and key haven't had any problems sence.