TC30 gauges maxxing out

[barnyardmechanic]

Hello,

I have a 2006 New Holland TC30 that has gauge problems that are driving me nuts. I have done a lot of looking on the interwebs, read lots of "fixes" and bought parts from my local dealer that did not fix my problem.

Last month, this just started one day when I went to move my tractor. When I start my tractor, the fuel and temp gauge got past the max setting, almost out of site. Takes about 15 seconds for them to move all the way. I am electrically pretty smart, When I disconnect them form their sending units, they drop back to zero, or the lowest reading. I can ground the sensor wire and the gauges max out. So the dealer said to replace both sending units, did that, same result. I have checked and re-did the grounds on the tractor and everything looks perfect. I tried a jumper from the ground terminal on the battery to the ground on the fuel tank sender, the ground wire to the gauges, and to the alternator. No bueno, still go to max. I have 14.5 volts with the tractor running. I pulled the gauge cluster apart looking for broken or burned wires or connections, nothing, all looks fine. I took the actual gauges out of the cluster and inspected them, again all looks fine. I did a terminal to terminal continuity check thru the wiring and the gauges and the little coils in the gauges aren't broken or burned up. I am now out of ideas, I really don't want to go buy new gauges, not at $200 each. If I have to, i will just go get universal gauges and put them on, but would be nice to get it working the way it is supposed to work.

 

[barnyardmechanic]

ANYONE?????

 

[DwayneB]

I bet a new cluster is expensive.

 

[JC-jetro]

So I gather , you are not having an overheating and issue is just he gauges? what is normal position of the needle ? on my 1700 which is a lot older than your TC30, with the engine off the temp gauges is pegged all the way passe the hot. If I short the one single lead attached to the sender to the ground then the gauges goes to Cold or pegs all the way to the cold/left side. When I put the key and turn the tractor on then the gauge would stay at cold and slowly creeps up as the engine warms up. In my case, if the wire is broken to the sender or pulled out the sender needle pegs to the right. I liked it as it would give me situational awareness id i am overheating or gauge wire is snagged , pulled off or busted. You have to check what is the normal position of your gauge when tractor is of first. if they have done same control sequence like what I have on your TC30 then I think you have an open to the sender. Do you see change of state in the needle when you short out to the ground the sender wire? there has to be a change of state. Your sender is just a resistance type. On cold engine my sender read about 700 ohm , operating temp around 140 ohms and 66 ohm , skosh to the left of max heat.

JC,

 

[Agvg]

Usually there are a voltage regulator for the instruments that deliver a stabilized voltage so the instruments. Did you see any such thing? As both fail they could have a regulator supplying both.