Ford 555D electrical

mohoghead

New User
Our 555D backhoe alternator isn't charging the battery and the battery light stays on, i'm getting 12Volts off the big red wire on the alternator, but the engine dies when we remove the battery cable. can anyone tell me where that wire is routed, the starter is directly behind the fuel filters so without removing them I can't find where the wire ties in to charge the battery.
 
does it matter where it ties in?

if you are reading 12v there,t he wire is intact and you are reading battery voltage....
 
(quoted from post at 13:21:14 08/17/15) does it matter where it ties in?

if you are reading 12v there,t he wire is intact and you are reading battery voltage....
hat souNdguy says & it 'probably' ties to the battery via the fuseable link, just based on other Ford tractors of that era.
 
Then may I ask why it dies when we remove the battery cable, and the battery goes dead after a few days of use.
 
(quoted from post at 14:00:17 08/17/15) Then may I ask why it dies when we remove the battery cable, and the battery goes dead after a few days of use.
ractor is running off of the battery.........you disconnect the battery & it dies.
 
well, think about what you typed.. and what I typed.

battery has power.

alt ( probably) has no power.

wire from back of alt goes to battery

thus measuring wire at back of alt means you are measuring battery.

ignition on a gasser needs power to run.. or if it burns fuel oil and has a fuel solenoid... both need power.

Now.. you wonder why pulling the battery wire off kills it.

where did we determine power was.?

answer: battery.

thus disconnecting battery takes power away. ( assuming alt is bad ).



I believe you are making the mistake that by reading power at the back of the alt, you think alt MUST be making power.... when in reality, you are reading bat voltage thru the intact wire!

a couple more troubleshooting steps would verify or deny this theory.

one, measure battery before and after start, and compare to measurements to back of alt.

remove battery wire and wire at alt and ohm the wire out.

those tests would remove all doubt.
 
this may help you understand what I typed.

alt's don't charge a 12v battery by putting out 12v.

alts charge a 12v battery by putting out 13.8-15.1 volts.. 14.4 being a common output, depending on vreg module or regulator setting/adjustment.

Thus if you are reading 12v.. that tells me you are reading static bat volts.. not 'charging' volts.. which, defacto, have to be more than static volts.. ie.. alt has to be at a higher potential ( more volts ), in order for their to be current flow from alt to battery.

if alt put out a max of 12v, and battery was at 12v. there would be no current flow, thus no charging.

that's why an alt putting out 14v charges a nominal 12v battery.. the source is at a higher potential, thus there is current flow..
 

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