TC30 Starting Problem

[jn9230]

2008 NH TC30, 670 hours.

I wonder if someone could verify something for me:
I believe I have detected a short in the electrical system, but I need help to verify. This TC30 has fallen victim of the no-start issue discussed for other NH and DX tractors.

So here is my question: When I disconnect the negative battery cable, I get continuity between the positive battery post and a known good ground point on the firewall. This seems incorrect to me, and an indication I have a dead short somewhere. Can someone verify if this for me?

There seems to be a slight draw (.2v) on the battery when connected properly (12.5 volts at battery posts). Trying to diagnose, I find that when I pull fuse #1 (5A to Safety Controller and Park Brake switch), the draw goes away (12.7 volts at battery posts). This could be enough to drain the battery.

Related info:

• Tractor has been garage kept its entire life, never left outside in rain or harsh conditions, never mistreated. Has had regular maintenance. Has been reliable until one day a month ago it just quit out in the field.
• Tractor will not start or even turn over.
• New battery – 1 month old, 12.7 volts.
• Added starter solenoid relay modification as discussed in TC33D won’t start thread.
• Fuel solenoid tested good, with 12+ volts. Cleaned connects best as I could.
• Good fuel at fuel bleeder point (have not checked for fuel at injectors).
• No blown fuses. Cleaned and re-seated all fuses.
• Tested parking brake safety switch with Ohm meter, tested good.
• Tested seat safety switch with Ohm meter, tested good.
• All wires appear to be intact, no critter damage, fraying or corrosion anywhere.
• Voltage and Ohms checked both positive and negative battery cables on and off the tractor. Cleaned both ends and made shiny off the tractor. Applied dielectric grease where appropriate. Both cables tested good with perfect continuity. No damage. 12.5+ voltage at starter solenoid.
• PTO and Neutral safety switch not tested, but visually appear to be in perfect condition, no damage or wear and tear, rubber protector in perfect condition. PTO switch believed to be good because dash light comes on when PTO is engaged, and goes out when disengaged.
• Removed the ignition switch and Ohms tested all contacts to appropriate connecters with key in STOP/RUN/START positions. Seems to be working as it should.

I am at a loss. I’ve spent hours trying to diagnose this, and am at my wits-end. I don’t know what else to check or test. Please help!


UPDATE:
After doing all of the above, I decided to quit until I can determine next steps. So I pulled fuse #1 (so to stop any power draw) and put the 12v charger on the battery. I then sat down to type up the above.

After 3 hours, I went back out and reinserted the fuse, and the tractor started right up instantly, no hesitation at all. I ran it at various RPMs for over an hour and it never hesitated. It ran perfectly. Thought I was done, but also thought the true test would be if it started up again. When I shutdown and tried to restart, it would not even turn over; even with the charger still connected. I could hear the fuel solenoid engage, but not the starter solenoid.

Battery had 12.5+ volts when not running and 14.5+ volts as it was running, so I believe the alternator is working.

I’m still a little suspicious of the key switch, and possibly the starter relay modification (although I followed the directions clearly).

I’m totally baffled now…please help, and thank you.

 

[Dman1981]

Does it start when you jump starter
Seriously some systems need 12 volts at starter solenoid do you have that with key if it starts everytime jumping it check voltage from key and all neutral start switches a safety switch with corrosion or high resistance can make something not work properly

 

[jn9230]

It started 1 time with the battery charger on it, but would not start again. It does not start every time when jumped.

I had 12.5+ volts at the starter solenoid.

I checked the seat and brake switches with an ohm meter, seems to be working fine.

Just checked the fusible link wire, and it is good.

Thx.

 

[TractorTech]

The ignistion switches are not the greatest and I would suspect it. If it won't start, try jumping at the small tang on top of the starter solenoid to establish that everything there is good. Then work your way to the starter relay mod and so on.

 

[nyone]

It started 1 time with the battery charger on it, but would not start again. It does not start every time when jumped.

I had 12.5+ volts at the starter solenoid.

I checked the seat and brake switches with an ohm meter, seems to be working fine.

Just checked the fusible link wire, and it is good.

Thx.

Intermittent electrical problems like this can be very time consuming to fix. You really need to be ready with the time and tools to check circuits every time you go to touch the machine.

To seriously cut down on your diag time I would make up a jumper wire for each safety switch and put them in. If the machine never has a problem again you know it's one of the switches. If it does have the problem again then it may be your key switch.

Did you check the neutral and PTO switches?

 

[jn9230]

Did not check neutral and PTO switches, but...

• PTO switch seemed to be working because dash PTO light comes on when engaged and off when disengaged.
• Both PTO and neutral switches visually checked perfect. No damage, tampering, or disturbance of any kind, and also rubber dust covers where in perfect, like new condition, so I thought both switches would be fine.

However, I will take your advice and make jumpers for all four and eliminate them. Will try to get that done today and will start the hunt for a new or crossover ignition/key switch.

Thanks much for your input, I will update when I know more.

 

[jn9230]

UPDATE:

Ohms checked all safety switches. All are working. Placed jumpers on all four anyway. No change (no start).

Bypassed first the negative battery cable by disconnecting it, and then adding my own separate cable from neg. terminal post to frame ground. Ohms tested perfect. No start.

Then bypassed the positive battery cable by disconnecting it, and adding my own separate cable from the pos. terminal post to the starter solenoid. Ohms tested perfect. No start.

I now suspect the ignition key switch or the safety control module. Both are expensive but it looks like I'm running out of options. Gonna have to bite the bullet I think.

Still would like to ask if someone with a TC30 could test if there is voltage from the positive battery terminal to frame-ground. I'm getting about 1/2 volt, and I think this is not normal and an indication of a short somewhere.

Thanks much.

 

[tmeric7]

Still would like to ask if someone with a TC30 could test if there is voltage from the positive battery terminal to frame-ground. I'm getting about 1/2 volt, and I think this is not normal and an indication of a short somewhere.

I completely understand this feeling... "I'm pretty sure I know the way it should be, but..." That's a good diagnostic mentality! I have a TC29DA and I tried to recreate your test. I keep the battery on a tender, but removed it first. After that, and throughout, the battery read 12.86V from '+' to '-' terminal.

I removed the '-' battery cable and measured the voltage at that '-' cable (so essentially, frame ground). We think zero, right?... It was 5.9V and falling very slowly (in the 0.001V digit)! I'll provide some interpretation on this in a minute (which is perhaps better than wild speculation). This was done with the key switch in the OFF position.

I turned the key switch to the RUN position and measured the same voltage at the '-' cable (still disconnected from the battery terminal) and it read flat zero, as we would expect, right?

I turned the key switch back to the OFF position and now it read about 5.6V and rising slowly. I went back and forth with all this and found it all fairly repeatable.

Strange, right? How can one read any nonzero voltage in two points in an open circuit? My suspicion is that there is some component in the system with a capacitive characteristic storing some charge for "awhile". I left the '-' cable disconnected and I'll measure it again in the morning to see if that "residual voltage has dissipated". But again, those nonzero measurements were in the OFF position. It was definitely zero in RUN.

It does not start every time when jumped.

I had 12.5+ volts at the starter solenoid.

I'm interested in exactly what you mean by this. So you jumped +12V to the spade terminal on the starter solenoid and that works sometimes? At this point I think you just have a bad starter, but I'm surprised this wasn't commented on before.

The key switches on these are known to be "not great". That could certainly be a contributing factor (or THE problem), but the info above does not jive with that for me. Still replacing it is not money wasted, even if the problem is not resolved. I replaced mine with a NAPA part that others on here suggested. I'm sure it's both better and cheaper. This is it:

https://www.napaonline.com/en/p/ECHKS6600

 

[lman]

What voltage do you have while cranking the starter? I had a starting issue with my NH 1530 and finally bought a new battery. I've been running the new battery for about 5 years now and no more issues. I have replaced the key switch on it about 15 years ago.

 

[tmeric7]

Update from my post last night: That voltage reading in the OFF position dropped more (it's a really slow drain) to about 4.2V. Battery voltage post-to-post was now 12.84V.

My current thought is that your 0.5V drain is a red herring. With a good battery and good cables connected to starter and ground, a 12V signal to the starter solenoid should energize the starter motor. Failing that, we need to look at the battery, the cables, and the starter motor itself.

Battery: Good suggestion from Iman, but you said the battery was new. Nevertheless, good to check that voltage reading. Mine is a little above 10V while cranking. Could also try jumping in another good battery to check.

Cables: These forums present examples of where these NH cables (especially) pass a resistance test, but because of internal corrosion, cannot carry the current to power the starter. I'd use a pair of jumper cables: '-' to frame ground, and '+' to the high-current terminal of the starter (careful not to ground out!) to provide a parallel pathway for current to get around a potentially bad cable. I suspect bad cables would also show a low voltage across the battery while cranking.

Starter: Failing all else, replace or rebuild. I know I've seen "failed starter" posts on here, so check those first before biting the bullet!

The intermittent nature of your problem may suggest cables or starter over the battery.

One more thought on the 0.5V measurement: It could be a parasitic loss that would eventually drain the battery to where it's insufficient to start the tractor. But if you keep a tender on it, I suspect it would never be an issue. Good luck!