X540 Nightmare, Help!!

[daisyman]

Not to be rude - but this post implies there is something wrong with your technique. You should have got the same result with either method and should not move forward until you have rectified this anomaly.

I agree with you 100%. I makes absolutely no sense to me either. That's why I am so stumped. I know you can not have voltage on both wires, one of them has to be ground. That's the reason I can't move forward.....I don't know where to go next. I'm usually very methodical and have tried every normal means of figuring this out, but this things got me whooped. I'm leaning toward what has already been suggested, and that's a bad ground. I think I might have a broken wire in the loom somewhere but of the MANY tests I've made everything checks good. As I said, I found one more connector behind the frame below the motor. I'm going to have to pull the deck off again to see where it goes. I found the clutch wires when I first started and they're fine.
Irv

 

[daisyman]

The B lead in the connector should be chassis ground... period. a point previous to X5 may be an open connection

assuming the diagram posted and linked is correct....


the A lead in the connector should be battery + voltage and since the diode is reversed biased should not reduce or affect the DC + available at that terminal.

that said I would back probe B terminal with a jumper to battery ( - negative terminal ) while everything is hooked up and PTO set to on with all conditions normally met for a functioning running PTO and see whether the PTO Clutch locks up and spins the PTO

I still have doubts since the same X5 is also the ground for the starter relay...

You may also want to check the outgoing Voltage and fuse itself
7.5 amp fuse 502b (blue wire) incoming to fuse and see if the test light comes on when trying to start PTO test light alligator clip to good ground.


ps. after all of the suggested help if that that fuse is just bad :confused2::laughing:

View attachment 524042

The first thing I did was change ALL the fuses. I tested them all and they checked good but I pulled them all out changed them anyway.:laughing: After awhile you suspect everything.
I haven't done anything on it today. I mow yards and had to do 6 of them and didn't get started until noon, the grass was so wet from the dew. I finished the last one when the sun went down. Maybe tomorrow. I need a break from that thing.
I'll check out all your suggestions when I go back to it
Thanks
Irv

 

[Spanner]

I agree with you 100%. I makes absolutely no sense to me either. That's why I am so stumped. I know you can not have voltage on both wires, one of them has to be ground. That's the reason I can't move forward.....I don't know where to go next.

Ok. Well let's go back a bit.
Dan's post in #21 is good info. Do you understand all his terminology? Just say if there are any words/terms you aren't familiar with the meaning of.

Ditch the multimeter for now.. The test light probe is all you need initially. You just need to know if you have voltage...

Connect the alligator clip directly to the battery negative (-ve) terminal. Not the chassis or any old bolt-head. The battery is the source of the power and you need to know power is going back to it. OK?

Now to test the PTO clutch initially, disconnect the 2-wire connector (X7) under the chassis. You then need someone on the seat (weight) - or to jumper the seat switch (for testing purposes only).

Key switch in the Run position or Run-&-Headlights position. (That's Power ON)
Brake pedal released.

Insert probe into the A terminal of the X7 connector which has the 501A/F BLUE wire.

Activate the PTO switch.

Does your test lamp glow?

Don't move, change or do anything else but:
Swap probe point to the 'B' terminal of that same X7 connector with the BLACK wire.
Does your test lamp glow again?

Report back here.

 

[daisyman]

I hooked my test light clamp to the negative side of the battery, and put my probe on the wire ends in the connector, one at a time.....it lights up on BOTH of them with NO switches on!!


I just went out and took my voltmeter and did the same test,... nothing. I turned on the key, activated the deck switch, pedal out of park and seat switch jumped, again nothing!!
How can I get a bright light on my probe with no voltage??

By the way, I've got a good industrial GREENLEE digital voltmeter, so I'm not worried about that.

 

[Spanner]

If I read you correctedly:

"I hooked my test light clamp to the negative side of the battery, and put my probe on the wire ends in the connector, one at a time.....it lights up on BOTH of them with NO switches on!!"

Was this with the connector still joined to the PTO clutch?

If power is present at the PTO connector (X7) with no switches 'On', including the Key Switch, you have a problem further back in the loom.

Check for power In and Out of the terminals on the Key Switch. You should have live power at the Red wire and NO power at any other terminal with the key 'Off' or even better, right out of the switch.

 

[daisyman]

No, I had it disconnected from the clutch. And I agree, there's something goofy somewhere. I've made so many tests from every conceivable way, I've about forgotten what I HAVE done.

It's 10.30 PM here and I'm going to hit the hay and give this another go tomorrow when I've got some daylight. My old noggin is full of confusion.
Irv

 

[Zebrafive]

I hooked my test light clamp to the negative side of the battery, and put my probe on the wire ends in the connector, one at a time.....it lights up on BOTH of them with NO switches on!!


I just went out and took my voltmeter and did the same test,... nothing. I turned on the key, activated the deck switch, pedal out of park and seat switch jumped, again nothing!!
How can I get a bright light on my probe with no voltage??

By the way, I've got a good industrial GREENLEE digital voltmeter, so I'm not worried about that.

First, is your test light non powered? I could see a continuity test light (self powered) lighting if the power wire at X7 is shorted to ground. It would also light when checking the ground wire.

If you are using a non powered test light, that the tractor battery is the source of power, are SURE you clamped to the Negative battery terminal? If you mistakenly clamped on the positive terminal, if the power wire of X7 is shorted to ground the light would be ON, same when probing the ground wire of X7.

If neither of these are the case, I would pull fuses, one at a time, to try and determine which circuit was feeding the wires at X7.

Have you put your meter leads across the test light leads when the test light is ON? Still no voltage reading from the meter?

 

[daisyman]

Well, you're 1 for 1! My probe IS self powered. I bought that thing maybe a year ago and it was hanging on the wall in the garage, and I just went in and grabbed and started checking, never realizing it was self powered. Most of the time I use my meter and really never looked at it. It's got a clear plastic handle and the battery is visible but just barely. When you asked if it was self powered, I thought, of course not! Wrong! How dumb (or blind) can I get!! LOL
I have another cheapie NON powered one, and I went and checked for voltage with it and no, there's none. With all of the switches on there's still no voltage.
It's pouring down rain now, so I'll have to take a break and check later.

Thanks, Irv

 

[ruffdog]

Whenever I grab my test light, the first thing I do is test it on a battery. There is nothing more frustrating than spending a bunch of time testing equipment to find out your tool is not working.

 

[sd455dan]

The test light being self powered explains some of this... I (***-u-me-d) it was just a basic 12 volt (in circuit) powered incandescent style test light.

It sounds like we are now back to No input Voltage to the clutch A terminal, (your results for multimeter test under the normal all conditions met) for clutch lock up state.
A test that would be helpful would be to check Connection C 370b at the control module for 12 volts when PTO switch is set to run and (key switch set to run) , if there is no voltage available the PTO on /off/momentary switch itself may be bad.

EXCEPT

for post 6 and 8 which clearly sound like an Open ground from clutch b terminal... You measured 12+ volts at the clutch input A and then measured in post 9 a .54 Volt difference between the A input terminal and B (GROUND) terminal??..

This sounds like an open ground

I would suggest Doing that test again With the connector plugged in.

and also a Voltage test between B terminal and the Battery ( - ) terminal (once again all conditions met for a running PTO)

If this shows anything much over 1/2 volt then the ground path is open.


Hope this helps, and a bit confused by some of the test readings.