I have a Volvo EC250DL that the instrument panel (I-ECU) has died and went black. The a/c continued to work for about a week and now the a/c has stopped working, the key pad does not respond to any a/c commands. some of the other functions of the key pad do work. I have power and ground to all units and have gone over wiring. My question is should the ac control unit still respond to keypad buttons although the I-ECU is dead. Seems it should and Service manual, vcads and Prosis are vague on the subject.
Good day JR Previouse versions of this machine had by-pass for the AC as far as I know the "D" also has provision, if you can post the wiring diagram we can try to help out. Kind regards Uffex
if you look at the attachments, you'll see that the HVAC ECC is independent of the I-ECU except through the J1939 & J1587 links. I don't see the HVAC needing an input from the display to operate. If you look at the feed side, it is controlled directly by the ignition switch and as such has no fuse or relay independent of the ignition switch. Now keep in mind, your instrument panel is independent of the network , it is a slave to the HMIM ECU. There was an issue in some G series loaders where the display would go dark due to an improper setting. Perhaps you could reach out to your dealer for some feedback on that.