On an AD truck, the only gauge to change would be the fuel gauge. I've seen where someone modified a 12 volt donor used-gauge, that was compatible with the original 30 ohm fuel tank level sensor and put an AD decal on it. It worked well and looked original. The thing is you have to contort your body to get up underneath the dash and remove the cluster. But first you have to remove all the other gauge connections and be extra careful with that copper capillary-tube water-temperature sensor that you don't crack or crimp it during removal. You have to remove the chrome bezel around the cluster assembly and not break the glass. Once you have been through that ordeal with added choice words to boot, you will not want to mess around with a modified gauge hoping that it works and continues to work okay. Buy a new gauge that is already made for 12 volts and 30 ohms. This is one situation where if you cheap-out, you may regret it later.
I bought a 50 1/2 ton that had a half a 12 volt conversion job. I corrected the mistakes and bought and installed a new fuel gauge. No resistors or voltage converter needed. Worked well and fuel level sensing was as accurate as original. The guy I bought saw what I did and wanted it back.
Last edited by buoymaker; 07/15/2021 1:45 PM.
