I have a John Deere 310SE backhoe that keeps shorting/burning up the acc. relay pt# AR73144. I have found some wires in the engine harness burnt and have tried to unpin them from the connectors and pin in new wire due to the fact the harness is no long available new or used. I thought I fixed the problem last night, and when I got in it to move the unit around the yard it started to heat up and burnt the relay again. That is when the 4wd comes on and I loose all power to one side of the fuse panel and the alternator stops charging. I do know when this happens John Deere defaults to 4wd which is dumb... I am at a loss with what else could be causing the relay to get hot and burn up. I will run back threw the wiring harness again and see if I missed a wire or two. Is there anyone that has had this problem with a unit like this before?
Welcome to HEF Cody ! A serial number is needed to get accurate help. Are there any codes displayed or stored ??
I would get an ohm reading on the AC clutch magnet, there should be a spec in the service info to let you know what to compare your reading to. Once you know your resistance and system voltage you can compute the amps being draw easily.
I don't have a serial number as of now it is a 1997 model, it doesn't have any computers to have any codes. The machine is a 12 volt system. Checking the system I have 12.58 volts at the battery supply side of the acc. relay, with key on the small post has 12 volts. After start up the relay clicks and I have the power to the other side of the relay it is working like it should. The problem I am having is after the unit has been running for about a half hour the relay gets hot and starts to smoking/burning up. during this I have checked the voltage at the relay it is 14.5 volts. I am have trouble finding why after start up it is getting so hot. The relay my customer bought for it was from Napa auto parts, a 200 amp 12 volt continuous relay. I have read that I could be using the wrong relay. Or I still may have a short still in the system,
Welcome to HEF Cody Relays burn up from 1. Too much voltage applied to the coil. Charging circuit ever go over 15 volts? 2. Too much current passing through (think short circuit). This is the most likely candidate. 3. Contact chatter. Interruptions of the coil activation voltage at a high rate of speed can cause contact chatter, which creates arcing and heat.
No voltage stays a consistent 14.3 to 14.5 volts, I will check again. I did find a few wire's melted, I will keep going thru the harness and repairing as I find them.