Branson 4220 Instrument cluster problem

[au1mom]

We inherited a 4220, the tachometer, hourmeter, and temperature gauge on the instrument cluster have stopped working. I have replaced the alternator (it had gone bad). I have replaced the instrument cluster unit. I have checked all the fuses, and the fusible links, I've checked and verified the Preheat relay. The tractor will start, but I'm getting nothing off of those gauges. I am at a loss of what else to check. I have also checked the wiring from the battery (+) through the fusible links, as far as I can go to the Preheat relay


Update: So after calling and talking to gentleman in Texas, who had 20+years knowledge on Branson. I ordered a new Gear Assembly Unit, and a new Temp Sensor. Replaced both of those, and the whole instrument cluster works.
I did find that when I took the new gear assembly unit out of the package, the difference in my old one and the new one. The back of the gear assembly unit that attaches to the engine- the old one was spinning easily, the new one had tension on it. So in the future if you take that off and it's spinning easily the gear assembly is broken.

 

[Slowpoke Slim]

Can you tell if the instrument cluster is getting a good ground? That would be my next guess on possibilities.

 

[Cougsfan]

Is it just those three gauges? Does your fuel gauge work? Also, be aware that the tach is read by counting pulses from the alternator. The hour meter may be based from the alternator too (Not sure of that though). Replacing the alternator may have had some relationship to . As slim suggested I'd check the ground, and also might try putting a little dialectic grease on all the pins on the plug ins.

 

[bobmisi]

Just went through this with my 3820i and finally decided to replace all the fuses even though my son and i each had checked them all. After changing them everything worked. Bought a fuse tester and checked the fuses we pulled out and two were bad, but they both looked good when we eyeballed them. Start there fuses are cheap.

 

[au1mom]

Just went through this with my 3820i and finally decided to replace all the fuses even though my son and i each had checked them all. After changing them everything worked. Bought a fuse tester and checked the fuses we pulled out and two were bad, but they both looked good when we eyeballed them. Start there fuses are cheap.

I have a fuse tester and checked all of them. They are all reading good. I've checked relays and those are good too.

 

[au1mom]

Is it just those three gauges? Does your fuel gauge work? Also, be aware that the tach is read by counting pulses from the alternator. The hour meter may be based from the alternator too (Not sure of that though). Replacing the alternator may have had some relationship to . As slim suggested I'd check the ground, and also might try putting a little dialectic grease on all the pins on the plug ins

Thanks for your reply. I put the new alternator on. Nothing. The Fuel gauge is working. I unplugged the tach cable and when the engine is running the tach cable isn't turning. It is a brand new cable so it should be working. I don't know how to check the gear assembly unit, and can't find anything online about how to. I am also wondering if the temp. sensor is bad- I drained the coolant and took out the sensor, and am also trying to figure out how to check that, since it only has a single pole sensor ( I know it has to be with boiling water- but not sure what to ground it too?)

 

[au1mom]

Can you tell if the instrument cluster is getting a good ground? That would be my next guess on possibilities.

I have checked all the wiring, and can't find anywhere where the wiring is compromised. Since the fuel gauge is working I'm assuming the instrument cluster is grounded and getting power. Is that a wrong assumption?

 

[LouNY]

Thanks for your reply. I put the new alternator on. Nothing. The Fuel gauge is working. I unplugged the tach cable and when the engine is running the tach cable isn't turning. It is a brand new cable so it should be working. I don't know how to check the gear assembly unit, and can't find anything online about how to. I am also wondering if the temp. sensor is bad- I drained the coolant and took out the sensor, and am also trying to figure out how to check that, since it only has a single pole sensor ( I know it has to be with boiling water- but not sure what to ground it too?)

You can gently clamp the body with a pair of vise grips then measure the resistance from the wire connector to the vise grips.
Starting out at ambient temperature or ice water and watch the resistance change as the fluid temperature does.

 

[Cougsfan]

Thanks for your reply. I put the new alternator on. Nothing. The Fuel gauge is working. I unplugged the tach cable and when the engine is running the tach cable isn't turning. It is a brand new cable so it should be working. I don't know how to check the gear assembly unit, and can't find anything online about how to. I am also wondering if the temp. sensor is bad- I drained the coolant and took out the sensor, and am also trying to figure out how to check that, since it only has a single pole sensor ( I know it has to be with boiling water- but not sure what to ground it too?)

If your tractor have a tach cable then your tractor is considerably different than mine. My tractor has no tach cable, and as I mentioned it determines engine rpm by counting pulses from the alternator. If you have a cable and it isn't turning with the engine running, then there is probably some sort of mechanical problem with the cable drive rather than an electrical problem in the instrument panel. On my old Ferguson tractor the hour meter is actually tied into the tach. It was more truly a rpm counter rather than an hour meter (an hour will be registered quicker at high rpm's than low rpm's). Perhaps your hour meter/ tack relationship is the same as my old Ferguson? And perhaps your temp gauge problem is a totally separate problem.