Ford 555D electrical problem

[AK410BERRY]

My Ford 555D backhoe is not sending voltage from the ignition switch to the alternator to make it start charging. If I put a jumper wire on the alternator it will start charging. I have voltage leaving the ignition switch going to the alternator but no voltage at the alternator. What could be preventing the voltage from reaching the alternator. I have checked for damaged wires thinking maybe a rat had chewed the wires since the backhoe doesn’t get used very often but can’t see any damage. Where could I get a wiring diagram? Any thoughts or suggestions would be appreciated.
Thanks

 

[Andy Wickiser]

My Ford 555D backhoe is not sending voltage from the ignition switch to the alternator to make it start charging. If I put a jumper wire on the alternator it will start charging. I have voltage leaving the ignition switch going to the alternator but no voltage at the alternator. What could be preventing the voltage from reaching the alternator. I have checked for damaged wires thinking maybe a rat had chewed the wires since the backhoe doesn’t get used very often but can’t see any damage. Where could I get a wiring diagram? Any thoughts or suggestions would be appreciated.
Thanks

I'm not saying this is it but I had that problem on my 455D and it was that the temperature sensor in the battery box had become disconnected. Do you have the manuals? If not I have the full set which covers the entire D-series.

 

[AK410BERRY]

I have the manuals but the electrical diagram in it is very poor quality almost impossible to read. Some details I can’t read at all. Thanks for the heads up I will check the temperature sensor in the battery box. Can I just bypass the temperature sensor? Is it normal open or closed?

 

[Andy Wickiser]

I have the manuals but the electrical diagram in it is very poor quality almost impossible to read. Some details I can’t read at all. Thanks for the heads up I will check the temperature sensor in the battery box. Can I just bypass the temperature sensor? Is it normal open or closed?

Here's the page that shows the temperature sensor, simplified wiring diagram, and explains operation. In my case I just reconnected the temperature sensor. If you don't have voltage to the alternator I guess you'll have to trace things out. Are you sure your little light bulb isn't burned out? I know what you mean about the full wiring diagrams, really tough to read which is disappointing for a factory manual.

 

[AK410BERRY]

Not sure what you mean about the little light bulb being burned out

 

[Andy Wickiser]

Not sure what you mean about the little light bulb being burned out

I should have said charge indicator light as shown in the diagram #9. If it lights on the panel when ignition on but engine not running or alternator not outputting then it's O.K.

 

[AK410BERRY]

It doesn’t light up when I turn the key to the on position without the engine running. None of the indicator lights come on. I had not thought about that. I did check all the fuses and they are good.

 

[Andy Wickiser]

It doesn’t light up when I turn the key to the on position without the engine running. None of the indicator lights come on. I had not thought about that. I did check all the fuses and they are good.

Here's what my panel looks like if key turned to run without starting engine. Alternator Charge warning lamp on, Engine Oil Pressure lamp on, Buzzer sounds. If the bulbs are burned out they are easy enough to change. The reason I mention is that with some alternators the charge indicator bulb excites the field to get generation going. I'm not sure if this is the case with this particular alternator.

Also from the previous diagram main voltage to the battery appears to be a "home run" that is a direct connection to the battery as connected at the hot side of the starter solenoid (ie not through the ignition switch).

 

[AK410BERRY]

Thanks again. I wasn’t aware a bad bulb would case the alternator not to excite. I will check that today. I hope this is the problem. I have removed my alternator and taken it to a repair shop and it tested good. I now have it back on the tractor. Your panel looks a lot like mine. When I put a jumper wire on the alternator the tach works but no other lights come on in the panel.

 

[AK410BERRY]

I removed the instrument panel as far as removing the circuit board from the case. I looked at all the solder joints and see nothing out of the ordinary. I have battery voltage to the plug that connects to the panel. With ohm meter I verified continuity from the plug to the circuit board. With the ohm meter I verified continuity to bulb socket. Still using the ohm meter verified the bulb is good.
To summarize I have voltage to a good bulb but the bulb doesn’t burn. Seems like all that is left is the ground or lack of. What am I missing

 

[Andy Wickiser]

I removed the instrument panel as far as removing the circuit board from the case. I looked at all the solder joints and see nothing out of the ordinary. I have battery voltage to the plug that connects to the panel. With ohm meter I verified continuity from the plug to the circuit board. With the ohm meter I verified continuity to bulb socket. Still using the ohm meter verified the bulb is good.
To summarize I have voltage to a good bulb but the bulb doesn’t burn. Seems like all that is left is the ground or lack of. What am I missing

You're getting into the weeds I think. For that bulb to light 12V is provided on one side through the ignition switch and the ground is provided by the alternator. Anyway below is the flow diagram to quickly isolate your problem.

 

[Jim.ME]

If the indicator bulb has power from the switch and power "going out of it" to excite the alternator, it sounds like a broken wire or bad connection between the bulb and landing point of that wire on the alternator/regulator end as the alternator is the ground for that bulb.

 

[AK410BERRY]

When it says “ground warning lamp lead at alternator” is that referring to the same wire that I have been trying to get voltage to excite the alternator?

 

[AK410BERRY]

If the indicator bulb has power from the switch and power "going out of it" to excite the alternator, it sounds like a broken wire or bad connection between the bulb and landing point of that wire on the alternator/regulator end as the alternator is the ground for that bulb.

I will admit I am not an electrician. I struggle with this. Your diagnosis seems very logical. One thing that puzzles me is why none of the trouble lights are working

 

[Andy Wickiser]

When it says “ground warning lamp lead at alternator” is that referring to the same wire that I have been trying to get voltage to excite the alternator?

Yes, labelled INDICATOR (WARNING LAMP TERMINAL) below. You can even pull the connector off the alternator and just ground that terminal for the test.

 

[AK410BERRY]

Yes, labelled INDICATOR (WARNING LAMP TERMINAL) below. You can even pull the connector off the alternator and just ground that terminal for the test.
View attachment 165007

Thanks. I will try that tomorrow and post an update.

 

[AK410BERRY]

I grounded the warning lamp wire at the alternator as suggested with the key on. The light for the alternator came on. I reconnected the wire to the alternator and the light came on in the panel and after starting the tractor the tach started working and the light went off just like it is supposed to. But none of the other lights in the panel came on….oil pressure for example. I suppose I was dealing with a bad connection somewhere. At least this part is working. Now to figure out the oil pressure. Thanks for all your help.

 

[Andy Wickiser]

I grounded the warning lamp wire at the alternator as suggested with the key on. The light for the alternator came on. I reconnected the wire to the alternator and the light came on in the panel and after starting the tractor the tach started working and the light went off just like it is supposed to. But none of the other lights in the panel came on….oil pressure for example. I suppose I was dealing with a bad connection somewhere. At least this part is working. Now to figure out the oil pressure. Thanks for all your help.

Good to hear. The other instrumentation lamps work in a similar way so you should be set finding the problems.

 

[AK410BERRY]

Thanks I had a few minutes today to check the oil pressure switch and it tested good. I will check the bulb next. Yesterday when I had the panel open I only checked the alternator bulb. This time when I open the panel I will check all the bulbs.
Thanks for all your help