2004, diesel 4X4 automatic 36,734 miles. Have never had any problems before. Last time I drove it no problems at all. Went to start it a few weeks later and won't start. Turned over but the original batteries seemed weak so I tried charging it up. Still turns over but no start. Replaced batteries, still no start. Also the fuel gauge quit working at the same time as this problem. I know it has at least half a tank of fuel. it will run if i spray starting fluid inti it until it is burnt up. I tried the Dodge "key dance" but no codes come up at all. The little circle for the shift indicator goes away after all the dings when I turn the key on. The lift pump is not running although I believe it did when this first started. I have 7.6 volts going to the lift pump with key in the on position. I purchased a code reader but when I connect it and try to reads codes it give a link error. I have checked all fuses and the cigarette lighter has power. There is also power to pin #16 on the plug for the code reader. Does anybody have any ideas?