L4200 GSTC- Charging system problem

[Teg1928]

I've read some of the related posts but could find the key to my problem. Battery not staying charged. Started having charging issues over the summer. Battery was less than a year old, but was having to put the trickle charger on it but it kept running down. I figured it had to be the alternator. Replaced with new. Charged battery up but dead again in 3 days. Replaced battery (tech said old one was still good). Took old and new alternators to electrical shop and both checked out good. Guess I have a spare now. I even took the fuse out for the radio thinking it might be draining the battery - not. Replaced both Negative and positive cables with upgraded 2ga cables. Wire brushed all connection points and bolted negative cable to the frame (bare metal) and sprayed all connections with battery connector protection spray. Had to jump it to use and ended up stranded in the woods with it and get rescued by the neighbor last night. Ugh. Any suggestions would be much appreciated.

 

[Tooljunkie]

Firstly, i would check all the fuses making sure the connections are clean. Check for fuse links in wiring harness as well
Check for proper inputs/outputs at alternator. Usually the internally regulated alternators have a larger cable direct to battery which should have B+12 volts.
With tractor running it should be at least 1 volt above battery voltage.
Small wires on alternator are usually a control wire and an indicator wire. Unplug and test with key off and key on. Conditions on both wires should change.
If its externally regulated,then diagnostics get a little more complicated and a wiring diagram would be necessary at the very least.

 

[Teg1928]

Thanks Frank. I'll check the fuses and connections as soon as I get home. Gotta get that 4x4 hydraulic wheel barrow going as it is the time to be cutting and splitting some wood!.

 

[lugbolt]

It is an internal regulated Denso alternator. They are VERY good units, see only a few failures.

First things first. Check the belt tension. Loose belt will cause low charging. Belt is ok, then grab your voltmeter. You will want to see 13v minimum with the engine running at about 1500 RPM. If you have any accessories, turn them on (lights, A/C, etc). You still want 13v minimum. If it's lower than that, you now need to find out why.

On the back of the alt there are 3 wires. Sometimes 4 or 5 but usually 3. One is a heavy wire and leads through a fuse and then directly to the battery. That one should be battery voltage with the wire removed from the alternator. It should be exactly the same as the battery voltage. IF low or nonexistent, find out why (fuse, connector, etc). Then reconnect it, start the engine. It should be 13v minimum measured from the stud or larger wire on the alternator.

If for some reason you have good charging voltage and it's still draining the battery, you will need to track that down. Remove one battery cable from the battery. Put your voltmeter probe on the battery, then the other probe on the battery cable you just removed. You should read less than 6v. If you're seeing battery voltage, you have a "draw". To isolate the draw, remove each fuse until the voltage drops. Once it drops, you found which circuit is troubling...then start disconnecting accessories on that circuit until you find which one is your issue. It is important to note that a radio has a memory and the memory constantly draws low amperage battery power. So you will need to disconnect the radio from the circuit to do the testing.

I have seen a few that the glow plug timer or sometimes the relay will "stick" and cause the glow plugs to stay energized-and that will kill a battery quick, as well as hurt the glow plugs eventually. Usually the glow lamp in the dash stays on, but not always.

 

[Teg1928]

Thanks Lugbolt. That sounds very similar to my problem and the glow plug dash light does stay on most all the time. And Ah! the radio.... I had pulled the fuse marked on the fuse box cover for the radio ... but evidently whomever installed it had their own ideas on which slot in the panel to use as I heard a faint hiss from the speaker yesterday when I climbed onboard. So now it is truly disconnected. Thank you for the detailed instructions will hopefully get to it this weekend. Would you happen to have the part number for the glow plug timer/relay for the L4200? I have the Owners and service manuals but didn't see the part number for the relay. Will post progress. Much appreciated.

 

[Teg1928]

I changed out the glowplug controller and the energizer light on the dash acts completely different. Hardly ever comes on now. before it was on most of the time. No problems for a week now so thinking it is fixed. Thanks a lot. Tg