Tach and hour meter quit working on TC40D

[pepperalbert]

Good day all,
Tach and hour meter quit working, does any body know the OHM reading between the tach pins?I have disassembled the dash several times and find no "mechanical" problems Any input would be great

 

[jinman]

With the tachometer removed and facing away from you, measure the resistance between the top pin and right side pin. It should be 252 - 292 ohms. Next, measure the left pin to the bottom pin. The resistance should be 237 - 275 ohms.

There are several threads in this forum dealing with the tachometer circuit and the hour meter. Searching and reading may be helpful if you have not already done so. One even includes a circuit modification.

Have you checked the wire coming from the alternator? Check it for continuity. It's the pink wire in a single wire connector that runs from the back of the alternator all the way up to the instrument panel. It goes into the instrument panel connector on pin #20. If you are looking at the connector plug, it's on the lower row and one pin in from the left. If you are looking at the back of the instrument panel, it's on the lower row and one pin in from the right. The alternator sends a series of pulses to the tachometer circuit. It comes directly off of one leg of the stator and pulses at 1/10 the rpm of the alternator (not engine rpm). Also, check fuse #4. It supplies power to the tachometer circuit as well as the rest of the instrument panel. If all your other instruments are working correctly, then fuse #4 is good.

 

[pepperalbert]

You are all knowing........You should be called "The Wizard of New Holland"
Will do the test as recommended, and I have read the forums on hour meter and tach problems.
Once again thanks for your information!!!!!!

 

[pacerron]

You are all knowing........You should be called "The Wizard of New Holland"
Will do the test as recommended, and I have read the forums on hour meter and tach problems.
Once again thanks for your information!!!!!!

CARNAC the magnificent was... all knowing.
Maybe Jim needs a new headgear
I agree that Jim is always very helpful and furthermore has a pleasant attitude to go
with it:thumbsup:

 

[pepperalbert]

Come to think of it, the "Wizard of Oz" was all smoke and mirrors!!!!!!!! I hope Jim is not blowing smoke up the loader!!!

 

[jinman]

Come to think of it, the "Wizard of Oz" was all smoke and mirrors!!!!!!!! I hope Jim is not blowing smoke up the loader!!!

Oh, I quit smokin' years ago. . . but I do pass gas now and then. I try to not lead people astray, but I do make mistakes. I appreciate your kind words, but don't ever fail to challenge me if you think I'm wrong.

 

[pepperalbert]

I enjoy a person with a sense of humor!!!!!!!!!. I have been in the automotive business most of my life, an exchange of ideas is always welcome!!. I have found that there is always someone who has experienced a problem that I encounter and is gracious enough to share their knowledge. Thanks