Starting and Charging issue!

[Doclane05]

I have a Ford/New Holland 6640. My issue is that about 3 weeks ago I was baling and started loosing lights. Checked battery and it was not charging. checked alternator and it was bad. Bought a new Lucas to replace the Mag. Mar. 55 amp. Still no charge. Checked starter solenoid and went ahead and replaced it. Now the tractor will not start or click. Fresh charge on battery, new alt, starter sol. and checked all wiring with no luck. Any help and advice would greatly be appreciated.

 

[LD1]

Put the old starter solenoid on. That shouldnt effect charging anyway.

Who tested alternator and told you it was bad? How are you testing that it isnt charging?

3- wire alternator or 1-wire?

Have you checked fuses? Or traced wires to see if anything is broke, damaged, rodent chewed on?

 

[Doclane05]

The Alt. rebuild shop that is local to me told me it was good. Testing from B+ to ground with fluke voltmeter. it is a 3- wire (Brown=B+, Brown/yellow=D+, White/Brown=W) from what I can tell from the wiring diagram in the service man. All fuses are good and nothing on wire is broke or chewed through. went completely through wiring Sunday.

 

[Doclane05]

Also checked relays and those are OHMed good.

 

[Doclane05]

I have a single wire alt. in my shop but im not sure on how to convert from 3 to 1

 

[WranglerX]

Usually there is 12 volt on D+ lead from ign. sw. to initialize alternator to start charge sequence.... Have you checked that.... How about battery/ground cables are they corroded?...

 

[Harry in Ky]

You don't want to convert to a one wire. Fix what you have. The problem could be as simple as the battery temp sensor circuit. There is a spade terminal on the regulator that receives voltage from the temp sensor mounted under the battery tray. If that signal isn't present the alternator will not charge. If the alternator tested good, then that's one of the first things on the tractor to check.

Personally, when I run into cases where I suspect that circuit I will bypass the sensor circuit entirely and supply that spade with battery voltage through a 250 ohm resister. Have done that many times with good results.

 

[Doclane05]

Usually there is 12 volt on D+ lead from ign. sw. to initialize alternator to start charge sequence.... Have you checked that.... How about battery/ground cables are they corroded?...

Battery cables are both new and clean. I can not find which wire that is in the manual. Do you know which one that is?

 

[Doclane05]

You don't want to convert to a one wire. Fix what you have. The problem could be as simple as the battery temp sensor circuit. There is a spade terminal on the regulator that receives voltage from the temp sensor mounted under the battery tray. If that signal isn't present the alternator will not charge. If the alternator tested good, then that's one of the first things on the tractor to check.

Personally, when I run into cases where I suspect that circuit I will bypass the sensor circuit entirely and supply that spade with battery voltage through a 250 ohm resister. Have done that many times with good results.

My alt. does not have that terminal I believe I will post a picture of it shortly

 

[Harry in Ky]

If you don't have that terminal then something has been modified at some point in time. As far as I know, all forty series tractors, and many others as well had that temp sensor system. I'm betting yours did too. Both Lucas and Marelli alternators Ford used had the provision for it.

 

[LD1]

On the alternator....you should have a 1 and a 2 by the smaller terminals.

Terminal 2 should have 12v. Otherwise it wont charge. (wont energize the alternator). Terminal 1 is the wire that goes to your charge gauge/light.

HOW are you testing it to see if its charging? Are you taking a voltage reading or are you relying on the gauge/light on the tractor?

 

[Richard Clayton]

voltage gage

 

[Dftodd]

B+ is battery power and should be powered constantly.

D+ is the exciter and tells the alternator to start charging. Should be powered when the key switch is in the run position.

W is the tachometer input.

You could very well have a diode hooked inline on the wire that feeds D+ to prevent back feeding to the key switch.

If that diodes bad, it could very well be preventing power from reaching that terminal.

 

[dstig1]

I don't know this model but could there be a fusible link in one of the wires feeding the starter or charging system? It is a type of fuse but it is spliced into the wire and not in the fuse panel(s) so they can be very invisible if you are unaware. Ohming out the wires from battery to alternator and starter should tell you if there are any open circuits to investigate.

 

[Williy]

A simple way to find out if your alternator is charging is to
use a volt/ohm meter hold the leads on the battery and start
unit if needle or meter goes to 14+ its charging..
Have you used an ohm meter on your cables to make sure
they are not corroded? Just looking on the ends will not tell
if wires are good or bad.

willy

 

[YanmarFever]

How about where the negative cable goes to the frame for a ground?
Take it off and clean the cable and the frame to bare paint and re-install.