650H won’t start

[Alan Caro]

I have a 2004 650H that when you try to start it, it seems to cut power to the system,
I checked if the powershutoff was the problem by jumping both negative cables on the same side and it stayed the same

I also checked the negative cable for conductivity and it seemed to be working fine

any ideas on what I should check next?

 

[Alan Caro]

More info: The problem begun slowly as it became more progressive, sometimes after a few tries it would start and continue to start

other times we jump started it and it would start and continue to start without the jump starter in normal condition

we checked the battery connections twice and they all are fine

 

[BillG]

Under the hood on the left side, behind the dash is a series of relays. I don't have a diagram in front of me but pull each one and check the contacts. they can corrode over time. Clean them up and retry, put a little dielectric grease on each one. If you can check each relay while it is out.

 

[Alan Caro]

Ok hopefully tomorrow if I have the chance I will check those, is there a possibility for it to be the thermostat sensor too? I saw that on some john deere tractors the thermostat sensor gets bad and it does the same thing

 

[BillG]

No, this is just a basic tractor. The only electronics are the dash monitors and they don't prevent a 650H from cranking and starting.

 

[Diesel Dave]

If the relays prove ok, I would suspect poor main power connection at the starter terminal or defective key switch.

 

[Simon C]

Could you have a defective cable halfway through. Have done voltage drop testing to find one on a John Deere Powered Screw compressor with only 50 hours on it. The cable was cut off internally and could carry no load, but unit in warm shop could start with big battery pack boost. something to check carefully.
Simon C

 

[bobatack]

just another bad connection tale
Just last week I was out helping one of my friends on his place
They tried getting the skid loader started with no luck
It would preheat without an issue but when turning key to start it only turned the engine about 1 round and kicked out with seemingly low battery
So we tried boost starting it with same effects
I got looking around in the engine compartment and notice this main kill switch
Oh ok i just switched it off and on few times (not really knowing it would do anything)
Told guy to try again and bingo starts like nothing was wrong
So just a wild guess but there must have been poor connection in the kill switch

 

[Alan Caro]

Hello! Had some time to work on it, I checked the wiring with the power probe and noticed that there were 12V going into the starter relay and 9.0V going out of it, decided to go ahead and replace it and it has worked properly since then, might have been lucky there.

 

[Alan Caro]

Thanks for the help!