4250 electrical problems

[chuckthisout]

I've got an electrical issue with my 4250. My voltmeter is not working correctly. I have 12.6 volts at the battery but when I turn the key on the needle on the gauge will not even come out of the orange and the manual says that is less than 11.2 volts. When running the needle barely runs in the solid green left of the black. I check voltage at alternator and it's around 13.7 and manual says 13.2 is low end of in specs. Alternator is new and batteries are new. It has two 12 volt batteries. Also, the clutch on a/c compressor locked up and dealer told me if I don't have 14 volts going to compressor, the clutch doesn't engage completly. Compressor is 3 years old. Wondering if these problems are related. Tested the connections on alternator and everything seems to be in specs but on lower end. So I don't know if I have an open circuit some where or could the whole gauge cluster be bad and cause these problems? It has the investigator II. Sorry for the long post but I'm about to pull my hair out and don't want to replace compressor if I don't have the correct voltage. It's hot in that cab right now in southeast Texas. Thanks in advance and any advice is greatly appreciated.

 

[AJB-830]

I think 13.7 volts out of the alternator is fine. My new JD 6105R runs about 13.8 volts in hot weather. Only time it puts out 14.2 volts is after startup. Measure the voltage at the compressor and if 13 volts or more, that should be fine. I would think the compressor clutch would operate at anything over 12 volts. Al

 

[pms]

If engine is running and you have 13.7 at alternator but only 12.6 at batteries then you have a bad connection and or high resistance between batteries and alternator.Could be bad connections and or old burnt wiring.Your voltmeter is "telling" you there is a problem in your electrical system.A fully charged battery should have 12.6 volts with engine off.A voltage drop test will pinpoint your problem areas.Also make sure your batteries are hooked up correctly.

 

[Atwatead]

This tractor would have had two 6 volt batteries originally installed. We had a 4250 and two 4450's equipped this way. Always started fine. Don't know if having two twelves in parallel instead of two sixes in series would effect the charging. Your a/c should work fine at your present voltage. Is the compressor getting power? You should be able to hear the Nippondenso compressor click with the engine off, key on, with thermostat turned up and turning the blower on and off. The a/c could probably a separate issue than your needle reading low.

 

[Tx Jim]

(quoted from post at 22:10:34 07/18/15) It has two 12 volt batteries. Also, the clutch on a/c compressor locked up and dealer told me if I don't have 14 volts going to compressor, the clutch doesn't engage completly. Sorry for the long post but I'm about to pull my hair out and don't want to replace compressor if I don't have the correct voltage.

Two 12 volt batteries attached in parallel is the way my 4255 came from factory. Low voltage to compressor will burn up clutch but won't cause compressor to "lock up".

I'll suggest to check wiring bulkhead on RH firewall of SGB for corroded/bad connections. Also check circuit breaker board in front of dash on LH side in SGB for loose connections.

 

[chuckthisout]

All the connections at the circuit breakers looked good. I have swapped out the relay that runs right side of circuit board and no change. I'll go
through the bulkhead connections today and look at that. Compressor not totally locked up but takes two hands to spin it. I could hear it "click"
when energized and will also check the voltage today. Went through this same thing about three years ago with clutches on the compressor.
Had the original alternator rebuilt, got 14 volts to compressor, but gauge still didn't read right, but ran it like that up until a couple weeks ago
when original alternator went out again. That's why new alternator and batteries. Also, the beeper under dash doesn't work because it has no
power. I ran a jumper wire from battery to it, turn key on and it beeps like it's supposed to. All the other warning lights have always worked.
Don't know if that even matters but trying not to leave anything out. Thank you to those that have responded, I really appreciate the help.

 

[Lee B]

Connections looking good are not the only aspect to look at when you are at the circuit breaker panel. Problem could be tired circuit breaker not making good contact internally. Check the voltages on both of the terminals, when you find one that is not close to same voltage, it should be changed out. A voltage difference here indicates a lousy set of points within the circuit breaker. A few tenths of a volt might be acceptable depending on total cost to replace those guilty, but more than a half volt is suspect. Measuring from the end of the mounting stud itself can test the connection to the wire that is attached to it if the wire itself then shows a different voltage. Wire terminals also can be the problem as too many times the crimp isn't good enough or water has corroded the insides somewhat. Your dealer is prone to fabrications with 14 volt advice, 13.7 is NOT low, it is perfect for a warm alternator. These clutches will operate at 10 volts provided they have amperage at those volts. Slippage is very rare and points directly to low amperage supply in that circuit which may be the fault of a weak circuit breaker. It will show below 10 volts at that point in time however, so you should be able to easily find it with a real voltmeter. JD dash gauges that use colors of the rainbow can and do skew their readings by several degrees, can't imagine just how, but I do have one in a 4630 that I have double checked and know better than to believe for this very reason. It also reads off the scale when off - I'm thinking they shouldn't do that either, but I'm not going to buy another defective prone gauge. This one now runs mid yellow, that's good enough since I know it lies.

 

[chuckthisout]

Checked voltage at compressor and had 13.71 at 1500 RPM. I also have a relay on the compressor that draws power from the battery instead of the switch (I think). Clutch saver is what I believe it is called (don't know how well it worked). All the voltage readings at circuit breakers were 12.68 and 12.67 with key on and motor not running on the right side and I think I tested them on the terminal and not the stud. I'm not positive though but none of the readings were that different. I will double check that after reading your post. Took the face off of the gauge cluster and pulled voltmeter out, started tractor and checked voltage with gauge out and motor at 2000 RPM and had 13.65. So I think my gauge is no good and maybe don't have any problems at all. Maybe it was a coincidence all this happening but who knows. Going to get compressor, dryer, and expansion valve and see what happens. Got to get some hay cut. Thanks for the help

 

[JMS/.MN]

Just an aside since you mentioned Investigator II. Have 4450 with same, only one in the area. For years, dash lights/guages would work/not work at will. JD factory knows it has a problem with them. I solved it this way: Took off the hood, towards rear area, locate ground wires on 2 bolts...3 per bolt. They lose contact, so I soldered each three together, then soldered both to a wire running down to frame. If contact is lost there, I can clean up that spot, rather than taking the hood off to clean up the upper grounds. Always works now.

 

[Lee B]

Precision voltage readings (nice touch, thanks for that) all sound fine here, I would have tried a can of freon first. Clutch saver (working great by the way) would bypass the troubles outlined in previous post true enough, but it doesn't sound like it's much needed on this one. Stud/terminal issue test is not important until you have missing voltage somewhere, you only seem to be short on freon? Especially if this a recent development where the A/C is not working, even with a minor leak, one can of freon likely to last the rest of the summer, making compressor switch out a winter time, no hurry project. Don't ever use stop leak versions of freon in there, won't stop the leak but will pollute the entire system with stop leak compound and then you have to replace everything including the tubes and hoses. Hundredths digit on DVM often wobble one or even two points, please ignore since this much precision is a waste of time and worry. You are quite welcome, understood about making hay while the sun shines.