Caper35 -

Did they stop working at the same time? Or did the stop at different times? I also assume you mean the Tachometer (not speedometer) is working fine?

So if the speedometer is working correctly then you most likely have good power to the instrument cluster... I'm pretty sure power to the gauges comes in on pin #21 on the back of the instrument cluster & it's the same power that runs your tachometer, temp gauge, fuel gauge, & 540/600 rpm lights on the instrument panel. Again if they work power to the cluster is probably ok.... You could check fuse #4 but I bet it is ok..

Also check the connector & plug on the back of the instrument cluster; check all the pins for signs of moisture or corrosion... I believe Pin's #15, #21, & #24 are for the Temp Gauge so check those... (pin # are 1 -24... if you are looking at the back of the instrument cluster pin #1 is top left, Pin #2, 3 & 4 are below pin #1.... Pin #5 Top second row, #6, #7 ,#8 below... etc... etc)

I would test these two gauge issues separately....

Temp Gauge: (easy test)
You need to use a jumper to short out the temp sensor to ground. Pull the connector off the temp sensor & put the jumper in the connector (on the wire, not the sensor). Short the other end of the jumper to ground, then go turn on the key for a couple of seconds and if the gauge goes all the way to maximum, then it is working properly and you most likely need a new sensor. If it goes less than maximum or does not move at all, you need probably need a gauge. NH part # 86540855 (this is just the temp gauge not the cluster). There are other test but the above is the easiest...

Fuel Gauge:
There could be multiple issues to check here.... (I had a sticking sending unit float on my TC40D... so check that...) There are multiple things that can be wrong here... Again check the connector on the back of the cluster & check the connector at the tank sending unit for moister / corrosion.

First: if you put the 2 wires together at sender the gauge should read full.... (this only proves the gauge #1 moves & #2 wiring isn't broken or shorted)

Second: Test the fuel gauge in the cluster... Using & Ohm meter test the resistance between pins #14 & #21, it should read between 70 & 80 ohms. Then Measure the resistance between #14 & #24 & it should read between 188-220 ohms (on the deluxe models). if it doesn't the fuel gauge is likely bad..... NH part # 86540853

Third: The fuel sending unit in the tank is a variable resistor unit, so when the tank is empty, it should read 245 to 249 ohms. & when the tank is full, it should read 32 to 34 ohms.

Forth: You can use a Multimeter to check the resistance of the float. Remove the tank connector & hook it to the wires going on the sending unit, the resistance should decrease as you fill the tank. Not exact but the resistance should be about 140 ohms at half a tank.

Next suspect would be the wiring, so the signal lead (brown wire at the sending unit) goes to pin #14 on the back of the instrument cluster & the black wire is connected to ground. Power to the gauge comes in on pin #21 (as mentioned above), it's the same power that runs your tachometer, temp gage, and 540/600 rpm lights on the instrument panel. If all the above checks out ok, you could run a temp set of wires from the sending unit to the cluster (bypassing the harness) to test....

Sorry for the long post but hope it helps....

 

SuperDuty,

Thanks for the great post about my issues. I don't know when they stopped working as they were not working when I bought the tractor and yes I meant tachometer (Rookie owner). I am going to check out what you said and report back in a few days. Thanks Again.

 

Caper35,

No problem.... the NH had an issue of the gauge cluster developing condensation inside & sometimes causing havoc with the gauges... Good Luck... hope it is a simple fix.

 

SuperDuty,

I did some testing on the weekend and here are my results.

Temp Test

Did the temp gauge test above and it seems the sensor is gone as the gauge went to max on a ground test.

Fuel Test

Well this one was a big more involved as there are so many variables.

First Test - Put the two wires together, but the gauge only went to 1/4 of a tank.
Second Test - Tested the cluster and both numbers were within range.
Third Test - Tested the fuel sending unit and both numbers were within range.
Fourth Test - Tank already full, so couldn't test.
Fifth Test - Connected two separate wires to sending unit and straight to cluster, but fuel gauge only went to 1/4 Tank.

So I have to assume that there is an issue with the gauge moving after these tests.

Thanks Again.

 

Your Welcome....

Temp gauge sounds like the sending unit (cheaper than a gauge)


I too would think it is the fuel gauge at that point... NH definitely had some issues with gauge cluster developing condensation inside & sometimes causing havoc with the gauges...

I'm glad it helped (somewhat)...

 

Caper35,

I also remember another NH TC owner mentioning he had the same issue with the fuel gauge. He wound up opening up the cluster to remove the gauge for further testing & wound up cleaning up the connectors putting it back together & it started working.... Might be worth a try...