G'day all, new on here but i see there is a wealth of knowledge so hoping someone may be able to shed some light. I have a mid 90's 3cx that has just started blowing the B7 fuse. It will work fine for a while and draw 0.18 amps then out of the blue it will just blow the fuse. From what i can see on the wiring diagram the fuse only feeds the fwd/rev relays and the dump relay directly so i'm guessing the problem is in that circuit. I have had the panels and dash off and have found no shorts that i can see. Only place left to look is the dump switch wiring. The fwd/rev switch doesn't seem to have any shorts. Anybody had this problem before i go pulling half the machine apart? Cheers from Oz Bob
This reads like a wiring chaffing problem. Have you noticed the fuse burning open at any particular operation? Perhaps shifting from forward to reverse or reverse to forward with the wheels cut a certain way, loader arms up, down, or stroking, 4X4 engaged, disengaged, etc? Don't rule out the solenoid that actually commands the operation also as it's internal sliding mechanism could have worn through it's insulator over time and operations causing an intermittent direct short. Electrical gremlins can be an ongoing nightmare and a systematic approach is warranted to keep your sanity.
I agree it seems like a chafing problem. I did check all i could see and moved things around a bit but found nothing obvious. I did use it fo a short while last night and seemed ok. Will see how it goes. The fuse that is blowing is on a simple circuit that really only feeds the FWD and REV relays and the dump circuit. The solenoids are fused after the relays on their own circuit so they would blow different fuses. Hopefully it was just some chaffing that wasn't visible. Only time will tell. Thanks for your input