Green Tractor Talk banner

318 Electrical Again

2K views 12 replies 6 participants last post by  sennister 
#1 ·
Had a local mower repair guy that sees a lot of 318's, 316's, etc. try to find my electrical issue. Actually, he has another guy do his electrical work. The 1990 318(P218G) had been sitting fallow for a little over a year before I gave up on chasing the issue down. He had it a few months, and when I finally got around calling to check, he said that it had been fixed for several weeks, but he'd lost my number. So, my B.S. meter was pegged, and I was just wanting to get the mower back and never have to deal with him again.

After a blade and belt change, I started mowing. In 45 minutes it quit, same as before. No power anywhere. First things I checked were the 2 fuses. Here's what the 20amp looked like -
Yellow


The spade was welded into the holder...

Auto part


The fuse didn't even appear to be blown.

I love this machine, I do. But, it's getting really frustrating trying to keep it running. I guess I'll give it one more shot. I've got a friend that works at a local JD dealer, and he said to avoid their shop because tracing a short like that could come close to what would be a nice down payment on a new machine. Would anyone have any idea what would burn a fuse up so badly? :flag_of_truce:
 
See less See more
2
#2 ·
If the fuse isn't blown, my first guess is you are looking at the point of failure... The fuse holder. Either way you may be replacing it anyhow.

The issue could be that if the fuse holder isn't making full contact with the surface of the blade, it will start heating up. Heat up too much and it can weld the blade in or melt the plastic of the fuse. Much like running too much current through too small gauge wire.

It could be a short but that should blow the fuse.

That is my thought without being there to look at the machine.
 
  • Like
Reactions: KennyP
#4 ·
Looked closely with a magnifying glass, and the fuse element is definitely intact, so I'm thinking that the 'bad contact' angle is a good place to start. Certainly much less expensive to start with a fuse holder anyway.

Now, maybe I'm wrong but it looks like that the OEM fuse holder is sold as part of the harness, and not by itself - Part AM108845. Any problems using an off the shelf fuse holder, except for maybe the mounting spring clip not being there?
 
#6 ·
Steve, Check local auto parts stores for a blade type fuse holder, should be about $4. They can be found with 2 pig-tails and can be spiced into existing wiring. After installing new fuse & holder, ohm out pto coil...should be around 3.7-4 ohms. Bad windings get worse as they are used and are known to blow a fuse. Bob
 
#7 · (Edited)
Steve,

Your present issue is replacing the fuse holder, and you should inspect the wire sourcing it all the way back to the key switch if possible. Below is the wiring excerpt that shows the fuse connections. F1 is the 20 amp fuse...

Text Technical drawing Diagram Plan Drawing


While the pictures you posted above show that the fuse holder is the failure that halted your mowing session, I suspect that this may not have been the only the reason you had the tractor in the repair shop originally -- what were that symptoms you were chasing then? If it was the occasional loss of electrical power, then maybe a loose connection at this fuse has been an issue for some time. So do let us know all the symptoms you originally observed.

Do you have the TM1590 shop manual (the above excerpt is from that document...) as it has lots of diagnostic procedures and has the theory of operation of all the electrical and hydraulic sub-systems. This forum has lots of folks that can give excellent experience-based advice as well, as does our sister site Weekend Freedom Machines.

Once you get the fuse holder replaced, please report back as to what other symptoms you still are chasing.

Chuck
 
#8 ·
Steve,

Your present issue is replacing the fuse holder, and you should inspect the wire sourcing it all the way back to the key switch if possible. Below is the wiring excerpt that shows the fuse connections. F1 is the 20 amp fuse...

View attachment 708142

While the pictures you posted above show that the fuse holder is the failure that halted your mowing session, I suspect that this may not have been the only the reason you had the tractor in the repair shop originally -- what were that symptoms you were chasing then? If it was the occasional loss of electrical power, then maybe a loose connection at this fuse has been an issue for some time. So do let us know all the symptoms you originally observed.

Do you have the TM1590 shop manual (the above excerpt is from that document...) as it has lots of diagnostic procedures and has the theory of operation of all the electrical and hydraulic sub-systems. This forum has lots of folks that can give excellent experience-based advice as well, as does our sister site Weekend Freedom Machines.

Once you get the fuse holder replaced, please report back as to what other symptoms you still are chasing.

Chuck
I was looking at the schematic. What is the stuff in the lower right? The seat switch and brake safety stuff? The ones labeled A B C D
 
#9 · (Edited)
That is the items inside what is called the "TDCM" aka Time Delay Control Module which monitors the safety switches and will shut down the engine or not let it start if operating conditions are not correct for safe operation of the tractor/mower. Those items are outlined by a square box label A1 Time Delay Control Module on the diagram. physically it is a black box mounted to the steering column under the battery tray.
 
#11 ·
Got it so the switches send their signal there. The way they do it in newer machines is to hook them up in series so if the chain is broken the relay for the PTO drops power. Basically in series on the coil side of the PTO relay.
 
#10 · (Edited)
It appears as though your fuse holder is corroded. Based on the good side. Or maybe a bad connection in the fuse holder. That will burn the fuse on one leg and not blow your actual fuse because the current cannot get to the other side.That is not saying you still have an issue with something shorting out. But I would start there.
 
  • Like
Reactions: KennyP
#13 ·
Hopefully that takes care of it for you...

(y)
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top