I have a John Deere 80c excavator 2006 model and am having problems with starting it. Key in ignition position no lights. When I run a jumper cable from the hot side 24v to starter it starts like normal. I checked an am not getting 24 volts to the battery relay but I am getting 24 v coming out of the key switch. I am a bit mechanical but not great at electric. any advice would be nice. sorry this is my first post. Carl Zander
Welcome to HEF Carl ! Did you check that at the red/white wire to the battery relay? If so that comes from the "M" terminal of the key switch (which should be a red/black wire at that end). If you jump across the two large posts of the battery relay, will it start?
I did check the voltage at the red/white wire to the battery relay and I am getting no voltage. I am getting 24 volts at the Key red/black. I will try jumping across the relay posts this week and see as I am currently not sure. I thank you for your help.
There is a diode in that circuit called the V3 load dump diode. That diode is most likely open. It is located behind the seat, see below.
It will be later this week I will check seems the back panel is a pain to get off any trick as I have tried to get behind it to inspect. Carl Z.
Yes that cover is a pain. No tricks. Just screws and bolts, some might be hidden behind plastic plugs, some accessed through the fuse box cover, etc.
i think there are two hidden i am struggling with Excavator is in Kanab working on a RV park there and I live in chandler az so going up weds and will let you know how I make out. will Napa have the diodes if not who online can I use or should i go to RDO John Deere in town here?
Get from RDO. NAPA won't have those.
I am up in Kanab UT where my equipment is and want to know can I use a screw driver to cross these terminals or how due u suggest. Jumper cable from red battery 24v to black side of relay ? then start with key? Thank you again for your help. carl z.
Try jumping from the battery positive post to the red/white wire on the battery disconnect relay. Then see if it starts.
started right up when I went from positive battery post to red /white wire on the battery disconnect relay. thanks again so this isolates that it is the load dump diode? thanks again for the help. carl z.
does anyone know where I can get the diode holder I have tried to upload a photo but can not get it done. It is the fuse like holder that the 4 diodes go into. One of mine is compromised to the point I think I should replace it. RDO was not much help on the phone as they could not find a part number.
It should be item 22B in post #4.
out of my John Deere 80c I need the receiver piece for the new diode? I know they are not together like them come from factory JD is saying to buy the whole harness. Carl Z.
Deere does not sell that. I believe you will have to search for a Yazaki connector part number 7283-5028 (Assy 7321-9822). Or get creative.
got the new diode in and it starts perfect!! Thank you so much for your help. Carl Zander