DX 33 Starting Problem Fixed

[cardenharry]

I have been plagued by the starter solonoid clicking now for about a year and have read the various post by others at this sight. I did not experience a blown fuse. Today I installed the 30A relay that others have reported using to fix a low voltage problem and the starter comes to life like it has 24 volts going to it. The fix appears to be working as there have been no failures today. I did install a relay purchased at a local Napa store. I had not realized that local parts places would carry a relay with the pin numbers 30, 85, 86,87 as others on this sight have shown. Mine also had a pin 87a which I left blank. Member Farmall Aces helped me understand that. Thanks. Also thanks to Radiopoor, Ron and others who have contributed instructions on this.

 

[SteveInMD]

Glad to hear you resolved it. Could you post a cross reference list of NAPA vs NH part numbers? I think there are many people that could benefit from it.

 

[thclimer]

This sounds like this fix everyone needs to perfom who has had starting issues. I wonder if anyone could sketch the circuit diagram showing how the additional relay is wired into the existing starter circuit?

 

[cardenharry]

The Napa relay I purchased shows part # AR276
I also purchased a plug with 4 wires that plug into the relay part EC23. You do have to make sure the 4 wires are in the position to contact pins 30, 85, 86, 87 (and not 87a)
There are detailed pictures on this site from Jsheds. For those interested a search under TC33DA-Starting problems will furnish good instructions. I basicly followed the instructions that others furnished on this site.
(1) Relay installed under plastic on left side down low in a vacant hole in the steel plate. Attached the inline fuse 30A on the engine side on the same bolt.
(2) Ran the wire from pin 30 thru the inline fuse and attached at the bolt holding the battery positive to the starter.
(3) Ran the wire from pin 85 to ground. I attached to a bolt under the clutch area that holds a hydraulic line. (need a loop end here just like what is needed to attach at the starter.
(4) Unplugged the white plastic connector from the back side of the starter solenoid and cut it off along with a few inches of wire. Connected this white connector to the wire from pin 86 and plugs back to the solenoid.
(5) Take the cut wire that previously went to the solenoid and connect it going to pin 87 .
I saved pictures and instructions on what others posted and printed them out for instructions to follow.

 

[SteveInMD]

Well, I'm no expert at drawing circuit diagrams, and PowerPoint doesn't seem to supply standard circuit diagram objects to insert, but I did what I could. The attached PDF file is three pages showing the original circuit, the completed alteration to the original circuit, and finally the new starting circuit. There are things missing from the diagram, such as the original fuse, but since you don't touch that part I left it out to keep the drawing simple. The circuit is more complicated than I have shown, but it does show you what you need to know to complete this fix. I tried to use the same wire colors as Jsheds describes where I could, but the white wire was hard to draw on white paper. Let me know if this needs any clarifications and I'll do what I can.

 

[SteveInMD]

Did anyone find this useful?

 

[CCWKen]

Yes, that is a useful diagram. It highlights were the actual problem lies--The key switch or safety interlocks. Seems that adding another level of connections (relay contacts) is adding more faults to the system. At some point, the resistance in the key switch or interlocks will become higher and the relay will fail to trigger. Is it then proposed to add another relay to trigger this relay?

 

[SteveInMD]

I believe the problem is in the series of interlock switches. The solution works because it only takes a few volts and very little current to trip the relay. However, the starter solenoid is much less tolerant of low voltage. A relay is a mechanical switch and it can fail, but it most cases they are very reliable and will likely outlast the tractor. It is possible for the interlock switches to become so dirty or corroded that they completely stop the current flow but we haven't have any reports of that yet. Remember, this is a standard method of increasing the reliability of a starting circuit; not just a crazy idea dreamed up for this tractor.

 

[dqdave1]

I believe CNH is now using the relay in the starting circuit on new production. This says that it must be a proven solution to the system.
All the relay does is make sure that 12 volts is getting to the starter solenoid. I have heard that in the old circuits, it was dropping to 10 volts.

 

[MikePA]

Let me know if this needs any clarifications and I'll do what I can.

Great drawing, Steve! The only way I can see to improve it would be to include the relay part number, the fuse holder part number, wire size and and anything else that would be needed to implement the fix. That way people could use it both as a shopping list and instruction list. Some (all?) of this is listed in other posts, but having it in one place would be great.