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Discussion Starter #1
This is on my new to me 1985 430...A previous owner bypassed the original mower deck PTO wiring with another switch...Maybe the original switch was bad or it was done to bypass safety features.The rear PTO switch works as it should.Looks like the seat switch is bypassed...I want to see if I can use the original switch or a new switch in the original location...The original safety features are not so important to me as the switches being where they belong.
I searched but failed to find a decent wiring diagram for the 430...I have a lot of experience with vehicle and motorcycle wiring so in theory I know something :lol: thanks
 

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Here the schematic for the 430 above serial# 420469. Click on the pic to be able to enlarge it.
430 Wire.JPG
 

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Here's the correct one. Unfortunately it's split into 2 pics in the manual. The PTO stuff is mainly in the first pic.
wiring 430 1.JPG

wiring 430 2.JPG
 

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If you still have problems post your questions and maybe a picture or 2. I'm sure this group can solve it.:thumbup1gif:
 

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Discussion Starter #7
Thanks,that's a big help. I printed the diagrams...I see the part labeled "Time Delay Module", I assume it's a simple electronic device that may have caused problems with PTO engagement so it was bypassed.I have to remove the side panels but the module may be on the left side of the firewall. Right now the 430 is in an unheated garage and it's very cold so I won't be doing much on it until the early spring....I'll keep looking for a reasonable priced shop manual.. but I have found that with older stuff, online forums to be an excellent source of information that's often better ...
 

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I find that lots of unfamiliar owners at first blame the TDCM for issues that are not resident there and come from the wiring and safety switches surrounding it functionally. The module does fail occasionally, and it certainly can be damaged by a prior owner hacking the harness around that area, but since these modules are very costly and are a 'non-returnable' assembly from Deere, it is best to establish the true root cause before just throwing parts at it.

The shop manual, TM1591, has a section on the theory of operation of each circuit section with much clearer and simplified wiring excerpts. I will attach that section here:

View attachment 322, 330, 332 and 430 electrical fromTm1591.pdf


Let me call attention to the PTO specific wiring excerpt for the early tractors as seen below as well --
430 PTO wiring, early models..JPG

Note that the tractors with only a front PTO switch will have a jumper at harness connection X5, not shown here. Also not shown in this simplifies excerpt is that there is a connection from X13 pin 7 to the Neutral start relay such that the fuel shut-off solenoid is opened when the ground speed lever is in neutral and the PTO switch(es) are off (the condition that allows the starter to crank the engine...)

The first thing to check for a not-engagng PTO is that the fuse F2 is not blown and that the wiring to the seat switch is providing continuity from a properly working seat switch. The older tractors have a strip style seat switch that is subject to water damage if the seat upholstery is torn, so it may not be making reliable connection when the operator is present on the seat. Many tractors have this switch bypassed by a prior owner, but my recommendation is to restore all safety systems both for their inherent protection of you, and for a factory configuration which assists the members of boards such as this in helping you trouble shoot your issues.

If your fuse and seat switch are working correctly, you should see 12 volts on X14 pin 9 when the operator is present in the seat...if you don'd have this then you cannot yet blame the TDCM for the failure to engage the PTO. If you do have this voltage on pin 9 under these conditions, then look for voltage out of the TDCM on X13 pin 4 which supplies the enabled power to the front PTO switch. If present, then turn on the front PTO switch and verify that you have voltage at the front PTO at X10 and the light on the dash should light. If this does not occur, then trace the harness wires and connector & switch components for proper function.

Lastly, the early tractors had single wire PTO assemblies that used the chassis ground as the return path, so check for clean, tight connections on all ground connections. Poor ground connections can also cause odd behaviors of the TDCM itself, and because the engine in the 430 is on rubber mounts be sure to check the engine to frame ground strap for a good connection as well.

430 ground verifications from TM1591.jpg

Let us know what you find, and ask any follow-up questions in this thread.

Chuck
 

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Discussion Starter #9
Now I have a good understanding of the time delay and PTO electrical circuit...All done for safety with consideration for the operator bouncing on the seat...If there's a real problem with the time delay, it's easy to bypass it.. A substitution using a simple "Dead Man " pedal would work well but might be a troublesome to keep one's foot on the pedal all the time.
Supposed to be near 40F on this coming Wednesday so I might be able to check into this better...
 

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My bet is the original pto switch went bad and the owner wasn’t willing to buy a new one. I see that regularly.
 

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Discussion Starter #11
5-10 below 0 F the last few days, 55 today....I removed the wiring done by the previous owner replaced feed wire from the PTO switch...The front PTO now works from original switch as it should.I have no idea why he bypassed the original switch.....The seat switch is bad so I left the jumper wire for now...Thanks for the help..
 
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