NH TC33DA Starter Problem

[oldestgoat]

I did the starter relay mod about 15yrs ago and never had a problem since. 2004 tc33da 1000hrs. Recently had to replace the ignition switch. I've often taken those types of things apart and fixed them but this one was too gone.

 

[bellzey]

You could also do a starter relay mod. You use the small wire on the starter to trigger a relay that would actualy power the starter.

Thank you, that is a good Idea, but I want to determine if the existing relay is defective first.

Consider this,
Anything that is mass produced can have a bad batch. It only takes one component. The bad or marginal components could be used over the course of many years.
You could have 2 starters made with a bad component even if the starters were made in different years.
It may also be due to a poor design.

Thank you, that is an interesting thought, and entirely possible. I have seen that happen more than once. Take out a bad part and install a new one just like it. If that is the case, I am right back where I started and a new starter right now for an intermittent problem isn't an option. New starters are expensive.

 

[Williy]

Starter for NH TC33: $77 https://www.google.com/search?q=NH+...rome..69i57.3874j0j1&sourceid=chrome&ie=UTF-8

willy

 

[nyone]

Thank you, that is a good Idea, but I want to determine if the existing relay is defective first.

What I'm describing is really just the starter relay mod. It's been done many times.

 

[bellzey]

Thank you for your input. Maybe so, but voltage is likely to be constant. Turning the key on and off a dozen times and correcting the issue isn't likely to change the voltage, but you never know. Same thing with the battery cables. Possible that there might be a corrosion problem, but then again, changing the starter once before did correct the problem at least for a couple of years. However, I have been a tech. long enough to know that you never really know what the problem is until you find it. Thanks to all for the brainstorming. It's always good to exchange ideas.

I spoke in error. You are correct. At the time I did not consider that there are 5 or 6 relays in the starter safety interlock system. When you add up the voltage drops, voltage at the starter relay will be less. Resistance across each relay can change due to environment resulting in a higher current draw and greater voltage drop. That would also explain blown fuses that others have reported. Reported elsewhere in this thread is a reference to an OEM factory relay modification to solve the problem.

 

[bellzey]

You could also do a starter relay mod. You use the small wire on the starter to trigger a relay that would actualy power the starter.

I did some research and New Holland did offer a relay upgrade many years ago, but most dealers where not aware of it at the time. Thank you again for your input. I am thinking of just putting in a momentary contact switch that bypasses the interlock system all together for those odd times when the system doesn't cooperate.

 

[bellzey]

My first thought would be to "jump" the starter solenoid spade directly to the battery cable post when it acts up. Make up a jumper wire that you can slip onto the spade terminal after removing the existing start wire. When you touch that to the positive cable post the starter will crank (if it's NOT the problem). It shouldn't be too hard to do if you don't have a loader. With a loader, you might need to get a little more creative.

Thank you for the suggestion. I think we have narrowed the problem down to a design flaw in the safety interlock system which can be modified

 

[bellzey]

You could also do a starter relay mod. You use the small wire on the starter to trigger a relay that would actualy power the starter.

You are right on the nose Nyone. My bad.

Have you performed the starting circuit modification which has eliminated this type of issue on many New Holland and Case tractors?

Check Post #127:

TC33D wont start

I have not, but you are correct about the OEM modification.

 

[bellzey]

I would like to thank everyone for their information and suggestions. I believe we can all agree that New Holland messed up with the safety interlock system. I have not decided on a course of action yet, but at least I know what I need to accomplish to correct the problem.

 

[nyone]

I would like to thank everyone for their information and suggestions. I believe we can all agree that New Holland messed up with the safety interlock system. I have not decided on a course of action yet, but at least I know what I need to accomplish to correct the problem.

No they didnt mess anything up. It's just a complex system of mechanical switches. Mechanical switches in a dirty environment can and will fail. When theh fail they typicaly fail to the safest position, in this case it's the tractor not starting. That's better than the safety switch failing in the other direction or the tractor starting when it shouldnt.