ATTENTION! 5085M (5000 series) blows ignition switch fuse and won't crank

   / ATTENTION! 5085M (5000 series) blows ignition switch fuse and won't crank #1  

Bigfoot62

Veteran Member
Joined
Aug 5, 2008
Messages
2,485
Location
W. Central Louisiana
Tractor
JD 5090M; JD 5085M; JD 5083E; NH TN70A; Ford 2600
ATTENTION!!! 5000 series owners. (5M, 5E and the older 5XX5 series, and maybe others) "If you haven't had this problem yet, you will." And you need to know what to unplug so that you can start your tractor again.
EVEN if you've never heard of this, PLEASE read this thread. (You might even want to bookmark it) It will save you a big headache and a service call from the dealer. :eek:

I realize that I'm not the first with this problem, and certainly won't be the last. I wanted to post this thread for others that run into the same situation.

Here are the only three threads that I've been able to find on it here:
http://www.tractorbynet.com/forums/john-deere-owning-operating/213373-blown-key-switch-fuse.html
www.tractorbynet.com/forums/john-deere-owning-operating/356617-if-you-have-5000-series.html?
www.tractorbynet.com/forums/john-deere-owning-operating/367821-5205-will-not-start.html?

Earlier this year, I had a tractor mechanic at my farm working on the Blue tractors. New seals for the injector pump on the 2600, and new rockshaft seals on the TN70A. He looked at my two green tractors and said, "If you haven't had this problem yet, you will."
He showed me the two-wire plug on the injection pump, and said "when" (not if) it happens, unplug this and put a new fuse in it. He was right.
I didn't give it another thought until I tried to start the 5085M on Dec. 24th. It had been about a month since I ran it, and I wanted to let the battery charge for a few minutes while I loaded hay with one of the other tractors. I turned the key and nothing. No dash lights, no radio, nada. I thought, well the battery's dead. Went in the shop and grabbed my load tester, but the battery was fine. Now, I'm scratching my head. Then, before I could figure it out, it was lunch time. :licking:
After lunch, my brother did a web search on his phone and came up with one of the above threads. Then, it hit me. I remembered what the mechanic told me. Went back to the shed, unplugged the cold start advance, changed the fuse and all is good. Just for ref., the 5085M was bought new in '10 and has almost 900 hours on it.

In the first link above, TxJim posted:
Being a former JD dealer service manager it's difficult for me to understand why JD hasn't corrected the temp sensor that's had a history of failing since the mid 90's when the 5000 series tractors were introduced.:confused3:
I agree. I don't understand why JD just sweeps this under the rug. I've read that the sensor is about $50. Haven't tried to buy one yet, and don't know that I will. That brings me to a question.

What will it matter if I DON'T replace this sensor? Will my temp gauge still work? Will it crank fine in our winter weather? (Here, in LA, we bottom out around the low to mid 20's, and that's pretty rare)

Thanks again to everyone that makes this a great site. Hat's off to you.
 
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   / ATTENTION! 5085M (5000 series) blows ignition switch fuse and won't crank #2  
Yep, i bought another sensor, put it in & forgot to plug it back up. Winter's relatively mild here, if it get's to cold, i don't need to be on the tractor unless it's an emergency.
I don't know how i got by with the older tractors w/o all the gubment crap on them, they ran/started just fine without it:confused3:
I think i paid 42 dollars for the new one.

Ronnie
 
   / ATTENTION! 5085M (5000 series) blows ignition switch fuse and won't crank #3  
could try a circuit breaker fuse in it, it will reset itself.
 
   / ATTENTION! 5085M (5000 series) blows ignition switch fuse and won't crank
  • Thread Starter
#4  
could try a circuit breaker fuse in it, it will reset itself.
That wouldn't fix the problem. From what I can gather, when the sensor fails, it shorts the circuit.
 
   / ATTENTION! 5085M (5000 series) blows ignition switch fuse and won't crank #5  
ok, I was just going off of the replace the fuse and it is fine.
 
   / ATTENTION! 5085M (5000 series) blows ignition switch fuse and won't crank #6  
That wouldn't fix the problem. From what I can gather, when the sensor fails, it shorts the circuit.

Ditto what Bigfoot62 stated substituting circuit breaker for fuse won't solve the bad sensor problem.
 
   / ATTENTION! 5085M (5000 series) blows ignition switch fuse and won't crank
  • Thread Starter
#7  
TxJim,
What about just leaving it unplugged?
Will my temp gauge still work? (separate sensor?)
 
   / ATTENTION! 5085M (5000 series) blows ignition switch fuse and won't crank #8  
That sensor is used to advance timing in the injection pump for cold weather starting, which helps emissions.
 
   / ATTENTION! 5085M (5000 series) blows ignition switch fuse and won't crank #9  
on my tractor you just unplug it. i would replace it before winter it does help in starting.
 
   / ATTENTION! 5085M (5000 series) blows ignition switch fuse and won't crank #10  
TxJim,
What about just leaving it unplugged?
Will my temp gauge still work? (separate sensor?)

Sensor has no affect on temp gauge. Tractor will operate fine with cold start sensor unplugged BUT your tractor won't pass your ANNUAL STATE EMISSIONS TEST!!!!!!:D:D:D:D Just kidding but if it was my tractor I'd not buy the sensor down here in Texas.
 
 
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