TC35D Key Ignition Switch Questions

   / TC35D Key Ignition Switch Questions #1  
F

felixedo

Bronze Member
Joined
Jul 15, 2011
Messages
50
Location
Missouri Ozarks
Tractor
New Holland TC35D / Deere 1026R / Bobcat CT2040
About a year I took my 2002 TC35D to a local Kubota dealer to have some minor work done. The nearest NH dealer is over an hour away, and I figured they could handle it. For the most part, they did. Except that the ignition switch failed while in their possession, so they installed a Kubota switch. It basically works, but it's junk. The biggest problem with it being that the key is not locked into place when on. I have already lost a key in the field. Fortunately, I had a spare key to shut down the machine. The other problem is that it is a 4 position switch (ACC / OFF / RUN / START), and the original had a 3 position (OFF / RUN / START). I would like to go back to an original style switch. -current p/n 86405634

The issues: The OEM switch is set up for a proprietary 4 prong connector that was cut when the Kubota switch was installed. "Why don't you just buy the connector and splice it into the line again?" you ask. The connector p/n is not identified as a standalone piece. It is only a component of the wiring harness which sells for $1000.

Finally, the questions. Any 1 answered will get me moving forward:
-Does anyone have an idea of the part number for the harness end of the switch connector?
-Alternatively, can anyone tell me particular post labels (A,B,C,D) for the OEM switch? They are not labeled on the switch themselves.
-Can anyone identify for me which wire goes to which post?
-Can anyone identify a comparable 3 position, 4 post key switch that would be a suitable alternative? The most common aftermarket switches are only 15 amp and 3 poles that I don't think could handle the load. 4 position switches are more common.

Thanks in advance.
 
   / TC35D Key Ignition Switch Questions
  • Thread Starter
#3  
Thanks, thclimer. I think I can piece together that information and get what I need.
 
   / TC35D Key Ignition Switch Questions #4  
thclimer,

I cant get to the link you posted here. Can you resend it to me? I am in a similar situation having to identify ignition wires and install a new ignition switch. Thanks

-Jay
 
   / TC35D Key Ignition Switch Questions #6  
I am in the process of replacing the ignition switch again on my TC40, last replaced two years ago. The switch is cheaply made as I pulled the old one apart to see what the problem was. One of the slide terminal had gotten warm and deformed the plastic that holds it. It is not Bakelite, but cheap soft plastic. I think that the case switch IT28 may make a better replacement that someone suggested in an earlier posting. I am finding that New Holland replacement parts are not a good choice if there are other parts that can be used.
 
   / TC35D Key Ignition Switch Questions #7  
3E76A5BD-2285-4ED5-BED2-491109AE960F.jpeg

Starting from the top down #1-red, #2-orange, #3-red, #4-white
I had ordered a different ignition switch to replace the one on my TC40. As the ones that New Holland’s has are extremely expensive and don’t hold up well. I had order one from a case tractor. Looking at the old New Holland switch and wiring, I found that the two reds tested hot with the same voltage, these being the top or #1 and #3 line. I found that the white wire or #4 wire is the starter/solenoid wire and uses the top or #1 wire for power, this happens only when the key is turned fully right to engage the starter. The second #3 red wire supplies the power to the orange #2 wire.
The new switch has a BAT, ST, IGN, ACC, GRD posts on the back of the new switch. I found that the white wire hooks to the ST post, orange wire goes to the IGN post and the two red wires to the BAT post. I had to scratch my head about the two separate red lines, other than making it difficult to swap the switch out along with the larger gauge orange wire. It is because of this that I will use both red wires on the same terminals.
I made jumpers to connect the new switch to the old terminal block and tried just one red each time, the tractor started and shut down with either red wire and the glow plug light did come on.
 
   / TC35D Key Ignition Switch Questions #8  
pikewrench said:
I am in the process of replacing the ignition switch again on my TC40, last replaced two years ago. The switch is cheaply made as I pulled the old one apart to see what the problem was. One of the slide terminal had gotten warm and deformed the plastic that holds it. It is not Bakelite, but cheap soft plastic. I think that the case switch IT28 may make a better replacement that someone suggested in an earlier posting. I am finding that New Holland replacement parts are not a good choice if there are other parts that can be used.
Click to expand...
Do you mind sharing the part number for the new holland switch? My brother has a tc40 and he has problems with the switch.
 
   / TC35D Key Ignition Switch Questions #9  
I bought one from Amazon Case 282775A1, which has the typical metal case. The switch mounts with the key hole horizontally and is under 20 bucks. The switch has an accessory position, but nothing is wired to it. have no problems with the switch to date. The unit sees a lot of use. The terminals should be marked on the switch and wire it as i show above
 
   / TC35D Key Ignition Switch Questions #10  
keep in mind that almost any basic switch can be use but, you'll have to cut the new holland plug off and install female crimp terminals on each wire. Both red wires will mount to one terminal, so you'll need a female crimp terminal that has a male spade on it
 
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