Ford 7740 electrical problem

[Decexcav]

Ford 7740 Drain on batteries if left hooked up it kills the batteries batteries check good alternator checked good Not sure of where to look next suggestions? or any one else have this issue

 

[Harry in Ky]

Lots of 40 series tractors develop that issue, the SLE probably more so than the others. You're sure it's not the alternator itself or the battery temp sensor circuit? If that's the case you can spend a great deal of time tracing all the possibles, many of which are behind the dash/steering column area. Or get a battery disconnect switch for one of the battery cables. That's been done many times.

 

[Decexcav]

Lots of 40 series tractors develop that issue, the SLE probably more so than the others. You're sure it's not the alternator itself or the battery temp sensor circuit? If that's the case you can spend a great deal of time tracing all the possibles, many of which are behind the dash/steering column area. Or get a battery disconnect switch for one of the battery cables. That's been done many times.

Had the alternator rebuilt and it and batteries all checked good

 

[Roadworthy]

You can disconnect a battery cable putting an ammeter in series with the circuit. That will tell you the amount of drain. You can then try pulling fuses one at a time hoping to isolate the source of the drain. In newer tractors some things are always hot - even with the key off. You could also check the manual to see what the steady state drain should be.

 

[WranglerX]

You can disconnect a battery cable putting an ammeter in series with the circuit. That will tell you the amount of drain. You can then try pulling fuses one at a time hoping to isolate the source of the drain. In newer tractors some things are always hot - even with the key off. You could also check the manual to see what the steady state drain should be.

Agreed..... Its what I would do....