Tractor troubles: NO PTO, Forward, Reverse

[eam7]

 

You may want to throw me off this board.  The tractor is a McCormick MC100.  The build date is 2004, so it is essentially a late Case I/H Maxxum.  The tractor is power shuttle, MFD, and about 4500 hours.  I do have bootleg (no doubt) service and parts manual on computer.

 

This started with the PTO dropping out when pulling a 15 feet Bush Hog, at very little load, and with no noise or alarms.  No loose wires found anywhere.  Made it back to the house and parked.  Retrieved error codes -error 15 "PTO Switch".   The switch tested good, I had an extra switch, also tested good, but did not help any.  Seat switch tested good. 

 

Next morning, an add-on problem.  The tractor will not move.  With the shuttle lever in neutral, no alarm.  As soon as the lever is raised- alarm mode with a flashing "N" light-which will not turn off until key is turned off.  Meanwhile, the PTO light sometimes (on key turned on) goes into continuous flashing, sometimes normal and I can get codes.  Mostly "15", an occasional "16" (low voltage).  No fuse anywhere has blown.  PTO, Fwd, Rev solinoids and their wiring checked OK.  Clean ground OK, alternator good at alternator.  Two suspect readings:  PTO speed sensor reads 1250 ohms -book calls for 2700-3300- but I do find on the net where people say new ones are that low and work fine (?)--secondly, the 4th gear reverse lock out switch is mostly open, showing 15-20K at mid-stroke.  Please advise me how this switch could cause a problem- it is open most of the time.

Now, one other factor- the input current to the PTO switch is 11.91 V while input at the key switch is 12.39 V. This circuit shows about 10 ohms to ground, with the draw being all the way from the MFD solinoid (wire attached-10 ohms, wire removed- 60 to 90ohms).
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    I am not a mechanic or tech- but I do many technical things.  The service manual is a hard read for me in the electrical sections.  My local dealer where I bought the tractor dropped McCormick 10 or 12 years ago. When I talked to them I thought they knew even less than me.  No close McCormick dealers - only two in the state.  This is a great tractor except for the electrics/computers.

Advise: don't ever buy a tractor with advanced controls without a cab--water damage has caused me problems.  I have begun to suspect the FNR switch as a root cause and that It is pulling down voltage to the PTO controller and kills initialization.   Can anybody offer some help here.

[66 Series Farmer]

I'm no mechanic either but did own a mtx140 McCormick.  In general a lot of electrical issues can be caused by bad grounds or loose connections on +and - so I would make sure you are all good there. I had trouble on my 140 with the pto not staying on. It gets signal from the alternator and if the voltage is low or drops it won't stay running. I changed pto speed sensors, checked voltages, RE programed based on manual and never did it get. Guy I sold it to changed alternator and still has issues with it. It has less problems with 1000 and acts up more on 540. (This all started too after I had the pto fall out so to snap ring issues while mowing). When trying to fix the pto problem I read several forum posts and one potential issue that was brought up was the safety sensor in the seat. You might check to see if it has one, if it does, will bypassing it fix the problem? It was said that it can cause the pto to not work and potentially the neutral switch. 

[66 Series Farmer]

There should be a signal wire coming off of the alternator, makes sure it is in good condition and not broke or cut. 

[HydroTek]

Ayup, seat switch is the usual cause for the N flashing like you mention -- also check on the cab floor where the wire runs to the console, seen the wire get broken there  few times -- Another spot in under the seat cushion, especially if you have the "floating" seat -- the wire gets worn / cut from the seat moving front and rear

[eam7]

Adressing seat and alternator issues.  I have checked both, as per service manual. But, when you make a hundred or more checks, it is hard to say you did not make a mistake somewhere or check the wrong point or think your meter is on volts when it is on ohms.  Also, there is the chance that the cause is intermittent and you missed the fail.  Also, I did not check the alternator signal wiring all the way to the PTO controller. I'll get that today.

[TroyDairy]

I see you checked seat switch.  Try jumping it.... after owning many I really think that's your FnR issue.

But like someone said...the alternator AC pin not working makes PTO issues.  Witchcraft how and why a tractor needs a AC circuit.  Or I kinda think you maybe have a bad PTO module.  They are NLA and my dealer had a Co in Quebec rebuild mine for nearly 2000 bucks!  But what do you do?  Test alt 1st....it's the extra pun on back...can't recall the # on it 

 

@SDman

[TroyDairy]

1 minute ago, eam7 said:

Adressing seat and alternator issues.  I have checked both, as per service manual. But, when you make a hundred or more checks, it is hard to say you did not make a mistake somewhere or check the wrong point or think your meter is on volts when it is on ohms.  Also, there is the chance that the cause is intermittent and you missed the fail.  Also, I did not check the alternator signal wiring all the way to the PTO controller. I'll get that today.

Well....

Meter on that pin.  Have someone Rev up and down throttle and it will fluctuate.  You sound competent enough you'll get it but it's frustrating 

 

For "feel your pain"... my mtx120 has been warning me of low coolant for 4 years.  Harness must have a compromise somewhere we can't find.  So I just ignore and carry on (still irritating but I ain't/can't get new harness so?)

[HydroTek]

The pin on the alternator you are talking about is used to get a frequency reading of the AC circuit -- so RPM reading -- why the alternator rather than a sensor on the front puller of the engine, or the flywheel is anyone's guess

Basically this compares the RPM of the engine to the RPM of the pto and looks for a difference -- to indicate a slipping clutch pack

[JimG]

You may get a reading at the alternator but it may not be what system is looking for.

Have the alternator checked at an alternator to be sure it is putting out the right frequency.

Have had a bad connection at the alternator cause the pto problem.

[HydroTek]

Yeah, a bad connection can cause the frequency to be higher than expected -- the system is looking for a disparity from the calibration setting , done with the jumper in the fuse box

[Gearclash]

21 hours ago, eam7 said:

and with no noise or alarms. 

I would think if there was a problem arising from the alternator engine speed signal that the green light by the PTO switch (assuming there is one) would be flashing when the PTO shuts off.

As an aside, and I do not think it likely that this is your problem since you haven’t found any blown fuses, a short in a wire coming from the FNR-PTO controller can blow the FNR-PTO controller fuse and the result is a tractor with no PTO function and no Forward or Reverse.  

[eam7]

I measured frequency at the alternator, "W" terminal.  Well, first I checked alternator at 14 V, then "W" volts at about 6.7 V.   Then frequency at idle to high idle-   about 300 to 670 HZ.  What I did not check --thought I would today, but did not get to it, was to confirm that the signal is getting to the input wire at the PTO controller.  I thought these readings were like normal.

I now think that the F-N-R switch is the problem because the outputs do not match what I think the circuit drawing calls for.  In the attached drawing clip--I think the inputs are #2 from switched power, #4 from key switch, and #5 connects to the starter relay when in Neutral.  Also I see, when in neutral, an input 2 to output 3.  In Forward, input 2 to ouput 6, and, in Reverse, input 2 to output 1.  The problem I see is that in Neutral, I only get .761 V to output 3.  I would guess that it is water, or water produced corrosion in the switch.  Some years ago I had problems with this switch-- I would take the switch out of the tractor, put it in the sun for one hour and then the switch would work.  Finally had to buy a new switch- $325.  The current switch list price is $476.  don't mind buying one if it is a fix--- sure hate to buy and then have to say-"well, must be something else".

And in response to "GEARCLASH", no fuse has blown in this entire incident.

 

[HydroTek]

Yours have the flat rectangular switch that uses a magnet on the shifter (FNR) handle ?

[eam7]

to HydroTek    Yes--the FNR switch is flat, orange, has 6 pins, and activated by a magnet on the end of a lever.

Now I just noticed that on my previous post, I did not include a clip of the electrical drawing ---  so attached here:

[HydroTek]

Those are magnetic reed switches in there -- they will not carry much current without damage

those 2 resistors, if I remember right are 470 ohm

should be 2 magnets on the shifter stick for the Neutral position

Pretty easy to test, if you have a pocket screw driver with the magnet -- use your meter on the terminals, with the connector disconnected -- beeper or ohms setting

[eam7]

A bit of an update--   The F-N-R switch was  inputting 12+V and ouputting 12+ in forward and 12+ in reverse and 0.751 V in neutral.  I put the switch in the hot sun for 4+ hours and the neutral pulled up to 11.7 V.  I think this mean water ingression and likely residual corrosion.

Secondly.  My original error code was "15" which is PTO switch.  I checked it per service manual and OK.  I had a second switch which also checked OK.   But neither switch changed the failure.  I have spent a lot of time looking for voltage pulldown on the input 12 V wire.  Today, I checked the switch (actually both switches) and found that the switches are both leaking voltage to the no voltage side.  The worst case was 7 V one way 5 V the other.  My diagnosis of this is that the controller is aborting initiation due to the double voltage, i.e. 12 V on the "PTO off side" and 7 V on the "PTO on side".   My further assumption is that the PTO is failing to initialize and that is failing my F-N-R function.   

Any comments???

 

 

 

[HydroTek]

Was that Neutral reading done with the switch in the circuit -- connected ?

if so, the load may pull the voltage reading down because of the loss in the resistor

[eam7]

In reply to HydroTek ---  I am almost certain that it was under load to the PTO controller.   But I will recheck it again today.  I pulled the voltage reading from the connector to the flat, orange F-N-R switch.   Looks like I will need a new switch--if not now, later.  It is hard to believe that this switch was not sealed against water.  I would like to give the engineering team for this tractor a good tongue lashing.

I think I will go to my local tractor dealer today and try to get a PTO switch.  He dropped McCormick about 10 years ago, dropped Case IH about 20 years ago---but still has some left over parts--and has arrangements to get parts through other dealers (but his prices are high--I think maybe list + 10-15%).  He is now Massey Ferguson + Kiota.   Also, a lot of parts he does not have, and that means high prices + shipping.   I now go to Messick for some dealer-only parts.  But today, I would pay a pretty good premium for a part in hand.

[HydroTek]

There were 2 switches , orange and black, all the farm tractors that I have worked on used the black switch -- Been too long and I don't remember the difference in the switches tho

I have had one of the black switches apart, and it was potted so water should not have been a problem -- the little glass reed switches are of course sealed by nature of their design -- this was on a CNH switch, McCormic may have used a different vendor

The PTO switch was the same way -- early types were mechanical, but later used the reed switches inside -- there are 2 switches inside regardless of type -- one that makes contact in the on position and one that is tied to the yellow button , for off

Some of the models also used a flat switch and lever, much like your FNR switch

Messicks is likely the best price -- try also the CNH website, you can buy thru a Dealer there

[eam7]

An update on this project:  

1.  The "4th range" lockout switch, ordered a new one.  Though best I can tell this switch had nothing to do with my problems, as the switch is NO.

2.  The F-N-R switch's output all the way to the PTO controller is F-12+, N-11+,  R-12+.  I think this will work, though there is some damage to the switch, and may cause problems in the future.

3.  I found significant voltage across some outputs of the key switch.  Replaced the switch.

4.  I did buy a PTO speed sensor switch because the in service unit tested low at 1250 ohms.  I doubt it is or was a problem.

5.  I pulled the connectors off the PTO controller and checked every one for voltage to ground with the key switch on and for ohms to ground with the key switch off.   I found a variety of voltage drops, voltage on grounds, grounds on power wires.  Going to the electrical drawings, I find most of these problems converge on Connector #40 which is a 46 position connector (maybe about 30 in use) from side console harness to transmission harness.  I have had this connector open a week ago and it was clean inside.  My guess now is that this vertical connector got water (and dirt) ingression into the top half, and that I have corrosion where the wire(s) are crimped to the pins.   I am pretty sure it is corrosion, as no fuses have blown, and low level voltage drop and "crosstalk" is typical of corrosion.

I realize this thread has gotten fairly technical and of lesser interest to many.  But for those that have an interest, I hope to post a conclusion in the next few days.  I hope the connector repair is easier than I fear.

[HydroTek]

Glad to hear you are making headway

[CIHTECH]

9 hours ago, eam7 said:

PTO speed sensor switch because the in service unit tested low at 1250 ohms.

The pto speed sensor should read 2700-3300 ohm's. There is also a bulletin that suggests taking o-ring off of it and using thread tape. The thought was / is the o-ring held it out a couple thousandths too far and sensor would not read consistently. I am pretty quick to condemn a sensor that reads too close to upper or lower limit, like to see them in middle of range. 

Anytime an alternator or pto speed sensor is replaced you need to sync / configure pto & engine rpm's. 

FOLLOW THESE STEPS TO CONFIGURE PTO**

#1 WITH KEY AND PTO OFF INSTALL CONFIGURATION JUMPER***

#2 START ENGINE AND SET RPM’S 1000 +/- 50

#3 MOVE PTO SWITCH OR LEVER TO RUN POSTION; PTO LAMP WILL STOP FLASHING AND STAY ON, CONTROLLER WILL BEGIN ENGAGEMENT AND CALCULATE ENGINE VERSUS PTO SPEED, WHEN COMPLETE PTO WILL STOP AND LAMP WILL FLASH 4 RAPID FLASHES AND A SHORT PAUSE

#4 TURN PTO OFF THEN ENGINE, REMOVE JUMPER WIRE

***JUMPER POINTS ARE LOCATED TO RIGHT OF TOP FUSE PANEL IN THE 2^ND AND 4^TH HOLES