HELP! 455 AWS - blades stopped working while cutting, now it wont start

wesWilliams · Jul 17, 2019

Hi everyone,
I have had my JD 455 (AWS, PTO, cat-0 3-point hitch) since new 20+ years ago and love it.. does everything I ask of it and rarely complains.

Yesterday I was in a wooded area cutting some underbrush using the 60" deck - something I have done for 20 years. About an hour into the job the mower blades turned off by themselves. The engine was not under heavy load and the temp gauge showed about 1/3 the way up. I cycled the yellow push/pull switch and the blades would not re-engage. I next decided to cycle the engine itself... I took the engine to idle for a bit and then turned it off. I raised the cowl and felt the engine.. it was not "overheating" and I suspect the gauge is correct. Next, I tried to restart it and it would not engage the starter motor at all. Ended up pulling the mower into the garage and now I need help!

Status of motor:

Key in 'run' position: Dash lights up, glow plug light comes on as usual and then goes out when ready
Turn key to 'start' position: Nothing happens, lights on dash stay on but no starter. I can do this with headlight on or off. When Headlights are on and I turn the key to start there is no 'pull' on the battery and lights don't dim
Checked the seat occupied sensor (even jumped the plug with a wire to make sure)

Here are some things I am thinking about looking at:

Blade engage switch
parking brake engaged switch
temp gauge shut down switch
tracing the circuits that engage the started and blades - aughhh

Any help on the best place to start and what to look for is very much appreciated

Thanks a million,
Wes

tomplum · Jul 17, 2019

Start by servicing the connections at the battery and having the battery load tested. Many auto part stores will load test them for free. If the battery is low or has failed, check your charging system output once you are up and running.

Shaneard · Jul 17, 2019

I agree with start at the battery, you could have lost a cell in it and it has enough juice to light the dash but not enough to do anything else. If it test out fine start with plugs on the switch and make sure they aren't loose.

Amvcane · Jul 17, 2019

In addition, check all safety interlocks.

Zebrafive · Jul 17, 2019

Have you tried starting by "screwdriver" at the starter solenoid?

ch1ch2 · Jul 17, 2019

Not familiar with your mower.
Is there a safety interlock that will turn of the blades? Maybe when you back up? When you are out of the seat?

That same interlock will probably prevent it from starting.

wesWilliams · Jul 17, 2019

ch1ch2 said:
Not familiar with your mower.
Is there a safety interlock that will turn of the blades? Maybe when you back up? When you are out of the seat?

That same interlock will probably prevent it from starting.

Yup,
a few safety interlocks... for example if the blades are engaged and I come out of the seat it will kill the blades. I need to explore further the seat switch wiring.. so far all I have done is remove the switch and jump the wires.. need to trace wires back to see if maybe it came loose from the other end.. or maybe a fuse or something. Should be fun this afternoon.. will keep the forum posted.

wes

Kish318420 · Jul 17, 2019

There are actually two temperature devices on the 455, a temperature sensor which sends it's signal to the temperature gauge on the dash and a temperature switch which will shut off the PTO if it thinks the engine is overheating. If you have the TM, TM1517 (see page marked 4-20).

Check to see PTO cable has been pulled off the upper rear axle. Check if you have RIO switch (it might of broke). Check seat switch and it's wiring. Check brake switch and it's wiring. Check neutral safety switch and it's wiring. Finally check the safety interlock board for the two LEDs, (You need to put weight on seat) one is RED and the other is GREEN. Turn Key to on and look for the LED's to be on.

wesWilliams · Jul 17, 2019

K7LN said:
I doubt that you have a battery problem. I think if you find the reason for the no crank, you'll also have the cause of the failed PTO operation. Electrical connections are always suspect, and the possibility of pulling off a connector in the brush should be considered. Check your fuses, PTO switch and brake switch operation. The brake switch sounds the most logical at this point.

Thanks a million.. it was the brake switch.. must have caught a small branch just right and popped it pretty good. I'll order a new one.. in the meantime I did what anyone with a 20+ year old workhorse would do... i drilled out the rivets, zip tied it back together, put it back together with a couple of SS bolts and back to doing what it does best!

Thanks everyone!
Wes

Broken brake switch