Need Help Diagnosing Electrical Problems

[brucew6char]

Over the years, when I'm not using my 1986 L2550 Kubota that much, I'd find the battery dead. So I just put a battery disconnect and trickle charger on and let it go. I also recently noticed that the headlights weren't working as well as the emergency flasher. And a few months back, the key stop wouldn't work. That's when I learned about about the manual stop but that also doesn't work. So now I just lower the FEL and stall it out. Yesterday i couldn't jump start the tractor, so i got a new battery. Ran the machine for a couple of hours without stopping it. Noticed now that the temperature gauge wasn't working - a new problem. When I went to put the machine away, i stalled it and then immediately tried to start it. Wouldn't start and acted like a nearly dead battery.

So I'm finally going to figure out what's wrong. Charged the battery last night and it started right away. Battery voltage is good and at 1500 RPM, the voltage at the battery went up to a little over 14 volts. So I think my alternator is okay. Pulled all the fuses and they were okay. And now I get nothing when I try to start it. Also, none of the dash idiot lights come on. Started to look at the key switch but then thought since my head lights and emergency flasher also don't work, maybe it's something other than the key switch. And it got cold and started to rain, so i was done for the day.

Maybe I didn't seat the fuses correctly but that doesn't explain my other problems. When the weather improves, i plan on making sure I've got 12 volts at the key switch, light switch and fuse box. Recheck my battery connections for voltage drop. While a bad battery connection might prevent it from starting, i think a poor connection would at least be good enough for the idiot lights.

I think somehow all the problems are related but it could be just a string of problems that I ignored for too long. Any other suggestions on how to diagnose. Thanks.

 

[atsah]

Sounds like there is short to ground somewhere drawing and killing the battery, follow wiring as much as you can, you probably have a wire that wore from rubbing and is touching the chassis somewhere. Good luck.

 

[WranglerX]

Get volt meter and disconnect ground cable and put meter in circuit between battery terminal and cable... IF you get a reading you have parasitic drain on battery... .... Remove fuses or disconnect wires one at a time till meter reading goes away... What every you disconnected to make reading go away is the direction of your problem...

IF no reading on volt meter with engine off, key off, there is probably no problem.. IF you have not got voltmeter get $5 trouble light and connect it up, same procedure as meter only lamp will glow if drain, of no lamp then no problem...

I have about 4 test meters from cheap $29 to $200 digital and the $5 test lamp is my first go to tool...

IF battery is going dead while tractor is running, the generator/alternator is no functioning... No matter what volt meter says...

With new battery and alternator output at 14 (plus) volts dc battery should NOT be dead with just a few hours run time...

Also check you battery and ground cables where they attach to starter (solenoid) and engine/chassis ground connect point...


Dale

 

[TractorGuy]

Get volt meter and disconnect ground cable and put meter in circuit between battery terminal and cable... IF you get a reading you have parasitic drain on battery... .... Remove fuses or disconnect wires one at a time till meter reading goes away... What every you disconnected to make reading go away is the direction of your problem...

IF no reading on volt meter with engine off, key off, there is probably no problem.. IF you have not got voltmeter get $5 trouble light and connect it up, same procedure as meter only lamp will glow if drain, of no lamp then no problem...

I have about 4 test meters from cheap $29 to $200 digital and the $5 test lamp is my first go to tool...

IF battery is going dead while tractor is running, the generator/alternator is no functioning... No matter what volt meter says...

With new battery and alternator output at 14 (plus) volts dc battery should NOT be dead with just a few hours run time...

Also check you battery and ground cables where they attach to starter (solenoid) and engine/chassis ground connect point...


Dale

A test light actually works better than meters for this. May not matter on older equipment but most modern stuff will read a full 12V draw from active memory circuits. If the draw is enough to illuminate a test light it WILL drain the battery.

My first course of attack would be to check the ground cables at the battery and frame. If there is a separate frame you would also check the cable connection from frame to engine. Next I would clean all the fuse connections and replace the fuses with new. I have seen fuse elements crack and look good but not pass current more times than I can count. It's not common but it DOES happen.

 

[brucew6char]

Thanks all for the ideas. I'll add them to my list. I would have thought the battery disconnect would have eliminated the possibility of parasitic drain. The fuses are good, I checked them with an ohmmeter. The battery acted like it was going dead after running for a couple of hours but my assumption was based on just turning the key, seeing the idiot lights come on but not turn over the engine. After charging overnight, i disconnected charger and voltage was about 12.8 Then it started immediately and voltage went to 14+ so it looked like alternator was working at that moment.

A bad ground might explain it not being able to start and make it appears as a bad battery but still allow the key and idiot lights to function. But now, neither the key or idiot lights work. That's why I thought I first needed to see if I'm getting 12 volts at various points. Maybe some how in the fixing process i blew out the slow blow fuse.

Tomorrow 2/10 is cold and rain/snow for most of the day, so i probably wouldn't be able to look at it until monday, 2/11. will post test progress and result.

thanks again for the ideas.

 

[Zebrafive]

You could have unseen corrosion within the battery cables. Usually where the cable and terminal connect.

 

[brucew6char]

Well, the starting problem seems to be resolved. Summary, there must have been corrosion at several connections and i found the positive battery terminal, while screwed tight, could wiggle a bit.

I spent many hours cleaning all the connections but never found one that looked bad. After cleaning the positive battery terminal and the inside of the connector, then tapping the connector down with a hammer, i was able to tighten the clamp with no wiggle. and now, it easily starts.

Before starting the connector cleaning, i measured .009 amp parasitic across the frame and disconnected negative battery cable. probably not the reason my battery was going dead. Immediately after taking the battery off the charger, the battery read 13.6 volts. it dropped some but the battery was fully charged.

i suspected my battery disconnect was not functioning correctly, so i replaced it and also put it between the negative cable and the frame. prior to that it was between the cable to the starter motor and the starter motor. i wanted a place where i could disconnect without taking the engine covers off.

I'm not sure what the connection is between the frame and starter motor connected to the engine, but possibly there is some corrosion there. I need to look to see if there is a strap or rubber cushions between the frame and engine. either could cause problems.

i still have problems but at least i can start the engine.

the key stop, temperature gauge, and hazard switch don't work. I think i know how to proceed on these problem. but more rain and cold is forecast, so don't know when i'll get to them. i can run the kubota without these being fixed, so not as much urgency.

thanks all for the suggestions, it really helped.