1920 electrical problem

   / 1920 electrical problem #1  
A

AlbionWood

Bronze Member
Joined
Nov 4, 2010
Messages
98
Location
Albion, CA
Tractor
Ford NH 1920
The dreaded and hideous "electrical problem..."
Actually more than one problem, but I suspect they are related.
Instrument panel isn't getting any signals from the fuel tank, oil pressure, thermostat, or alternator. All dead.
Fuses are fine. Can't find any chewed wires or breaks. Took the fuses out and tested across the terminals, with key on but tractor not running: 12V across each of the 10A fuses, but only 6V across the 15A fuse.
Took off the instrument panel, cleaned out the mouse nest behind it, opened the plug connector and tested the various circuits: Less than a volt across each pair of pins.

The tractor starts and runs just fine. The alternator does not seem to be keeping the battery charged though. It has an Optima AGM in it and after a lot of use, the battery will lose power and eventually won't start the tractor. If I jump-start it and run it for a while, it does not regain charge. I've been using an old Sears charger periodically to keep the battery charged.

The only thing I can think of is maybe a relay has gone bad. Anyone have other ideas, or suggestions for additional diagnostics?
 
   / 1920 electrical problem #2  
check your grounds. start tracing
 
   / 1920 electrical problem #3  
How does you electrical box with fuses and relays look? Mine was buried in dust and dirt when I had intermittent issues. Remove every fuse and relay and clean the tabs and electrical sockets to start with. You might find a local auto parts place that can run a free check on the alternator/regulator. They might find a blown diode.
 
   / 1920 electrical problem #4  
I'd pull the battery, fully charge it and then load test it to verify you have a good battery.

Electrical trouble shooting with a bad battery can send you down all kinds of rabbit holes and waste a lot of time.
 
   / 1920 electrical problem #5  
My last rodent (mouse) encounter yielded a batch of chewed wires in my wiring harness that feeds the instrument panel. Very tedious job mending all of those wires. Hope your mouse was not as hungry as mine.
 
   / 1920 electrical problem #6  
kirkawilson said:
My last rodent (mouse) encounter yielded a batch of chewed wires in my wiring harness that feeds the instrument panel. Very tedious job mending all of those wires. Hope your mouse was not as hungry as mine.
Click to expand...

Those nasty mousies chewed my 1920 instrument panel wires right at the plug.
I did not feel that I could do a decent repair job.
Cost from Messick's was $240 for a new partial instrument panel harness.
 
   / 1920 electrical problem #7  
kirkawilson said:
My last rodent (mouse) encounter yielded a batch of chewed wires in my wiring harness that feeds the instrument panel. Very tedious job mending all of those wires. Hope your mouse was not as hungry as mine.
Click to expand...
Mouse or rat, they both eat wire. I just finished repairing the dash wiring on the old JD 420C. The fine 20ga. wire for the gauge lights was completely severed. The 18ga. ignition line for the charging light was bare wire and shoring to ground against the back of the gauges. The tractor has been sitting since before my hospital stay over two years ago so the rodents have had plenty of time to move in.

Had to change the water pump too and found a bird's nest in the belly pan. I smelled skunk while working on it and got nervous of the flail more sitting next to it. I've been spraying around the place the skunks come back after a week or two. :rolleyes:

Farm life, ain't it grand. :laughing:
 
   / 1920 electrical problem
  • Thread Starter
#8  
Tinhack said:
Farm life, ain't it grand. :laughing:
Click to expand...

Yep, I'd rather have these problems than other people's!

Update: I tested the relay and it's fine. (Learned a new thing today: how to test a relay.)
I don't have a load tester, but maybe it's time to get one. I think this battery is not the problem though, because I never have any signal to the instrument panel, even with a freshly charged battery, and no trouble starting the tractor.

So... it's down to tracing ground connections and looking for wire problems, and getting a load tester so I can check the alternator. Wish me luck.
 
   / 1920 electrical problem
  • Thread Starter
#9  
I can't find anything in either the owner's manual or the I&T that tells me which circuits the fuses protect. There are only three fuses, one 15A and two 10A. I measured only 6V across the 15A circuit with the key on, and that bugs me; seems like it should either be 12V or nothing. SO I suspect something screwy in that circuit, and I just need to figure out what it feeds so I can trace it out. Someone here must know off the top of your head what each of those fuses protects.
 
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