Cat 279D, serial number GTL 7066 Problem - HVAC system is blowing fuses while operating killing the blower motor. Replaced the fuses several times and as a test installed a 30 amp which also blew. Figured it was the blower motor so we replaced it. Machine worked fine for several days and now it's blowing fuses again. We have 2 - 279D's so swapped the fan controls out and they are not the problem either. So do we have a wiring issue or are there relays that could be causing this? When the blower is working the system cools FWIW. Thanks in advance.
Not familiar with your HVAC system specifically, but it sounds like you could have a blockage or restriction. Is there a cabin filter somewhere? A electrical diagram, would show you what else is tied into blower circuit, then you could try disconnecting, to isolate.
Schematic incoming.
Thanks Nige!
No it's not a restriction. Blows fine when working.