TC35 Tachometer Failure

   / TC35 Tachometer Failure #1  
Parfleche

Parfleche

Silver Member
Joined
Apr 26, 2006
Messages
106
Location
WA
Tractor
NH tc35a
Dear Folks,
TC35 tachometer not working, possible causes? Possible solutions?

Thanks in advance!

Kind Regards,
Steve
 
   / TC35 Tachometer Failure #2  
Check to see that all the other instruments and dash lights are working properly. If so, then your tach is driven NOT by a cable from the engine, BUT by a wire from the alternator. Should be a green wire off of a terminal on the alternator that goes to a connection on the back side of the dash panel. You should disconnect the ground cable from the battery, if you mess with the alternator wiring. It may be as simple as the cold making the needle stick and an appropriate bump to the bottom of the dash may loosen it up. Good luck.
 
   / TC35 Tachometer Failure
  • Thread Starter
#3  
Halftrack said:
Check to see that all the other instruments and dash lights are working properly. If so, then your tach is driven NOT by a cable from the engine, BUT by a wire from the alternator. Should be a green wire off of a terminal on the alternator that goes to a connection on the back side of the dash panel. You should disconnect the ground cable from the battery, if you mess with the alternator wiring. It may be as simple as the cold making the needle stick and an appropriate bump to the bottom of the dash may loosen it up. Good luck.
Click to expand...

Thanks! I will check it out.
Steve
 
   / TC35 Tachometer Failure #5  
tach.png


this is from my NH manual
 
   / TC35 Tachometer Failure #6  
I recently purchased a USED New Holland TC33D tractor. Good news is that everything on the tractor appears to work ok except the tachometer/hour meter.
There is a green wire with a female blade connector that looks like it should have been connected to something around the alternator but is hanging loose. There is a plastic connector on the back of the alternator with a black and red wire going from the alternator to the dash area + the large power cable off the back of the alternator.
As I understand it, the tachometer takes a pulse from the alternator to count pulses to show the tachometer indication.
I assume either the black or the small wires go to the "idiot" light on the dash--this light goes off when the tractor is started. I cannot find where the green wire might have been attached to the alternator. I have the wiring diagram in the back of the owners manual but no color coding of wires.
Any help would be appreciated.
'
 
   / TC35 Tachometer Failure #7  
I attached a couple of photos of the back of my alternator, hopefully adequate enough to give you an idea where the green wire plugs into it. Yours may be the case that the alternator has been replaced with a generic unit with no tach provision. Check to see if the mounting bolts have been removed or unthreaded. The wiring diagram is color coded in that the letter at the end of the description denotes the color.IMGP4397.JPGIMGP4398.JPG


And welcome to TBN
 
   / TC35 Tachometer Failure #8  
Halftrack said:
I attached a couple of photos of the back of my alternator, hopefully adequate enough to give you an idea where the green wire plugs into it. Yours may be the case that the alternator has been replaced with a generic unit with no tach provision. Check to see if the mounting bolts have been removed or unthreaded. The wiring diagram is color coded in that the letter at the end of the description denotes the color.View attachment 623562View attachment 623565


And welcome to TBN
Click to expand...

You don't know how relieved I am to receive your response. Thanks!!!
Now I know exactly what my problem is which will save me a lot of time and possibly unnecessary parts purchasing.
My alternator looks like yours and others that I have seen pictures of on the internet--but cannot really see the area where the green wire is attached on yours since I have a bracket in the way along with having the arm from the front end loader in the way.
As soon as I finish my morning coffee I will remove the bracket that is in the way--looks like a simple job and see if I have the correct alternator and if so determine why the blade connecter/wire was disconnected. I suspect that I have a generic unit with no tach provision-but will soon find out.
I earlier noticed that there are several alternators advertised on the internet as being "exact replacements" but guess I need to find out if they are really exact before I buy one if the wrong alternator is my problem.
Thanks again, my next challenge is to find out (curious) the manufacture year of the tractor and assume there is some way to find that out via the vin number.
Gerald
 
   / TC35 Tachometer Failure #9  
FarmerGerald said:
You don't know how relieved I am to receive your response. Thanks!!!
Now I know exactly what my problem is which will save me a lot of time and possibly unnecessary parts purchasing.
My alternator looks like yours and others that I have seen pictures of on the internet--but cannot really see the area where the green wire is attached on yours since I have a bracket in the way along with having the arm from the front end loader in the way.
As soon as I finish my morning coffee I will remove the bracket that is in the way--looks like a simple job and see if I have the correct alternator and if so determine why the blade connecter/wire was disconnected. I suspect that I have a generic unit with no tach provision-but will soon find out.
I earlier noticed that there are several alternators advertised on the internet as being "exact replacements" but guess I need to find out if they are really exact before I buy one if the wrong alternator is my problem.
Thanks again, my next challenge is to find out (curious) the manufacture year of the tractor and assume there is some way to find that out via the vin number.
Gerald
Click to expand...

All Grins on this end. Removed the bracket and there was a connector blade on the far side of the battery connection. Green wire connector wouldn't reach so, cut and spliced in a small section of wire and hooked up, re-installed bracket and gave it a try. Tachometer now works. Don't know the history of how the green connector got disconnected but obviously the harness wire would not reach the alternator.
On the other subject of year, etc. of my NH TC33D it has the numbers G043956 for the tractor number and 3H19D on the name plate---can't read what the 3H19D is for since paint scratched off also has an engine number and a transmission number but assume the tractor number or the 3H19D are the clues to the manufacture date.
Any ideas on the date of my tractor's origin?
Thanks again.
 
   / TC35 Tachometer Failure #10  
I referred to Tractordata.com and it appears your serial number would put it in the 2003 model year. I doubt if anything more precise is available without going back to the factory books. Glad you were able to fix the tach.
 
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