Another Tachometer/Hour meter failure question

[Tacklenut]

Hi Folks. Yes this another Tach/hour meter question.
This is a New Holland TC40D

I have searched and read the prior post post several times and would like to ask one more time. I pulled the instrument panel off. I measured the voltage at the pink wire at the instrument panel location. I get about 7.5 volts. I pulled the tach out of the gauge cluster and did the Ohm check. I get 127 reading at both the top post to right post and 129 from the right post to the bottom post. This is on the post of the gauge cluster. I read on a previous post about testing these.
On the gauge itself, I get 238 from the left hole to bottom hole, 275 ohms from top hole to right hole.
Does this mean my gauge cluster has to be replaced? I tried electronics cleaner and electrical grease to the post prior to removal.

I also get the glow plug light illuminating during operation from time to time. Not sure if this is related.

Thank you in advance for your input.

 

[Tacklenut]

I bought a new gauge cluster and have the same issue. No tach and no hour meter. All other gauges work fine. Power to pink wire is about 7.2 volts measuring with the adjacent ground wire on the cluster connection.

Anyone have a suggestion. All fuses under gauge appear to be fine. I am about done with this. May look for an after market hour meter.

 

[pepperalbert]

Hay my friend, I had the same problem without the glow light issue. One thing I did was to change the alternator because it was not giving me a constant 7.2 volt signal. Everything worked for a little while----then you know what happens, the tach and hour meter quit. Several articles have been posted about this problem but it almost rocket science to me. I have been contemplating installing a separate tach and hour meter. Let me know if you have better results. Would you sell your old cluster? Maybe it will function for me.

 

[Tacklenut]

Hay my friend, I had the same problem without the glow light issue. One thing I did was to change the alternator because it was not giving me a constant 7.2 volt signal. Everything worked for a little while----then you know what happens, the tach and hour meter quit. Several articles have been posted about this problem but it almost rocket science to me. I have been contemplating installing a separate tach and hour meter. Let me know if you have better results. Would you sell your old cluster? Maybe it will function for me.

I might be interested in letting one go. I would like to hold on to them for a little while to see if by some miracle I can resolve this. I just bought a new test meter and the instructions are about worthless. I retested the voltage at the pin connection again and got 15 volts this time. Not sure if I had it on the right setting. My friend used his tester and got around 7 volts. Switching both sets of gauges around did not solve my issue. The gauge cluster I bought was off Ebay with only 1 hour and 1/10 showing. It looks brand new and still no luck. Could be bad as well. I dont have a local NH dealer near by so I may have to call around to find help.

My owners manual has the wiring diagram showing the pink wire at the alternator and the black ground going to the starter bolt. Both wires seem fine. I crammed a wire up in the ground pin hole on the gauge and connected it to the block but no luck. Not being an electrician, I can see any other wires that would feed the Tach.