Hello, I just joined the group and really think this will be a good resource. I have a 2015 259D FTL05127. The AC isn't working and I was hoping for a little help. I did find a couple posts on related things but wanted to get specifics. I started with the fuse and it was missing? Installed a 20amp fuse, Blower works, compressor works, Cab switch works. Checked low and high side jumped but nothing. The relay has power to it on the smaller pink wire and the white. I'm reading that the low side switch turns the compressor on but there isn't any power at the connector. I'm looking at the wiring diagram but I'm not knowlegable enough to figure it out. Help
First up, kudos for posting a S/No. Saves having to ask for it. So it's blowing air out of the ducts but not cold air.? Have you looked at the electrically-controlled valve in the heater circuit.? That could possibly be stuck in the open position. #5 in the illustration below. If the water lines to/from the heater core are both hot you have your answer............
Yeah I thought the ser# would be a good Idea to post. I can check that valve. When I removed the AC relay and jumped the hot lead at the pigtail and lead from the pigtail to the compressor it turns on the compressor and blows cold air through the vent.
It’s not that valve stuck open if it blows cold air, at least I don’t think so.
I don't believe it is also. I need to figure out why there isn't power to the compressor or why there isn't power to the low pressure switch. I have the wire diagram but I'm struggling trying to follow it and trouble shooting it. If it was low on freon would that be a cause for no power to the compressor?
There is another 20a fuse that appears to be associated with the AC relay, it should have a picture of a fan blade on the fuse diagram. Might confirm that fuse is good also.
I checked that fuse and it's good. Thanks
With the engine running, unplug the machine harness from the 2-pin connector at the A/C low pressure switch and test the continuity of the switch with a DMM. Are the switch contacts open or closed.?
I can check that. There isn't any power to the low or high pressure switches using my test light. Shouldn't there be power on one side?
Not that I can see, but I don't guarantee that. It looks like the LP & HP switches when open or closed simply make continuity in a circuit back to the ECM. The ECM sees "open circuit" or "continuity" in that circuit containing both switches and acts according to the way it is programmed. The LP & HP switches are connected in series via wire # 597-AR17 Purple. Wire #519 Pink is the input from the thermostat. Wire # A510 Orange is connected to the ECM. On second thoughts it looks as though wire # A510 Orange at the LP switch could have power when the A/C is switched on.
So far I think it may be working. Replaces thermostat and high/low pressure switch. Thanks all