I have a cat model 277c that the lift arms won't operate any suggestions to fix it
Does your particular machine have a door or is it open cab.? To identify exactly what you have (there are multiple variants of 277C) please post a Serial Number.
KCC00271
So according to what I can see it has a closed cab with a door. Is that correct.? It's also a military machine. The "commercial equivalent" to obtain parts & service information is a 277C of JWF-prefix
Yes that is correct.
If you ever get stuck use JWF02310 as a Serial Number, especially for something like an electrical schematic. That machine was built on exactly the same day as KCC00271. OK, so you have a door. For your symptoms it could well be that either the door switch, or the wiring to it, has gone AWOL. I'll send you an electrical schematic but meantime you need to find "CONN 12". This is a 6-pin connector located to the right of and slightly behind the operator seat. See the illustration below. Zip-tied to that connector should be another 6-pin connector with one loop of black wire in it. Unplug the harness going towards the door and plug in the jumper harness which bypasses the door switch. If the bypass harness is not there then on the machine side temporarily jumper Pin 5 (Yellow) to Pin 2 (Black). If there is a problem with the switch or the wiring in the direction of the door the implement hydraulics should now work. EDIT: Use the jumper for TESTING ONLY. DO NOT leave it in place permanently. By doing so you are bypassing an important safety system that could get someone killed.