I am planning to replace the OEM oil pressure and water temperature gages on my 98 12 valve. I would like to insert resistors across the terminals on the on both the wires going to two gages so the CPU will see these gages as being in the normal operating mode. This should eliminate the out of operational chime from going off. Does anyone know what values the resistors should be to accomplish this task.

 

Not sure on the oil pressure but you can trick the water temp to normal with a 1000 ohm resistor.

 

I measured the oil pressure sender resistance at 50 ohms at engine startup cold and idle. I have had it with the factory oil sensors and decided to replace the factory oil gage with a blue digital oil pressure gage from Don's Sport Vehicle Sales. I installed a 47 ohm resistor in the plug I removed from the old sensor. This will fool the CPU into believing I have normal oil pressure all the time and my chimes won't go off. Also my CPU will not drive my oil pressure to zero anymore.
I also installed a water temperature gage and will be installing a blue digital voltmeter as well. I installed the new water temperature gage sensor in the 1/2 inch NPT connection behind the alternator. I still have the factory water temperature gage. I used the engine common ground connection beside the #1 cylinder valve cover to ground all gage connections. I used the black wire with an orange strip under the steering to get plus 12 volts. A Radio Shack inline fuse holder (270-1213) with a 5 amp fuse was used to protect the circuit. I connected into the tan wire on the light switch to connect to a variable voltage dimmer wire. This wire is the outer wire on the left as the headlight switch is pulled out.
I went with the top dash 3 gage setup from Diesel Performance Parts as this was a convenient way of adding three gages without reducing visibility.