Ford 6640

[agsnow]

PTO trouble shooting advice please! I need to go to the hayfield now.

 

[sotxbill]

PTO trouble shooting advice please! I need to go to the hayfield now.

Remember that the alt light must out... for the safety relay to engage.. If the engine dies, the safety relay drops out until it senses the alt working a gain... If the relay drops out, you must turn off the pto switch and turn it back on. Is the tach working?? fuses and relays must be working..

 

[sotxbill]

Remember that the alt light must out... for the safety relay to engage.. If the engine dies, the safety relay drops out until it senses the alt working a gain... If the relay drops out, you must turn off the pto switch and turn it back on. Is the tach working?? fuses and relays must be working..

Fuse #21 is the pto fuse at 5amp rating. combo relay 5 and 6 or V and VI are the pto safety relay. If you see the light come on at the pto switch, then you need to trouble shoot hydraulics, solenoid, valve and pto clutch..

 

[agsnow]

OK thank you ! .., the fuses ck ok; not familiar with PTO solenoid location or how to test at this point. Please offer any guidance about that test.

 

[showcrop]

2X PTO safety relay! Cab or open? If the ambient temp of that relay is too high it can open when it shouldn't.

 

[agsnow]

2X PTO safety relay! Cab or open? If the ambient temp of that relay is too high it can open when it shouldn't.

Ok, I have open cab.... Thanks, Good to know. Do you know what fuse and relay that might be?

 

[showcrop]

Ok, I have open cab.... Thanks, Good to know. Do you know what fuse and relay that might be?

On my 8240 it was bottom row and it was a yellow cube relay.

 

[agsnow]

On my 8240 it was bottom row and it was a yellow cube relay.

Alright, I will look again. And and no, my tach is not working when cold.
Thanks.

 

[agsnow]

Remember that the alt light must out... for the safety relay to engage.. If the engine dies, the safety relay drops out until it senses the alt working a gain... If the relay drops out, you must turn off the pto switch and turn it back on. Is the tach working?? fuses and relays must be working..

Someone posted years ago pics with an explanation with a jumper wire for PTO relay delete.
I have run mine like this for years now and don't have or recall if the relay was working, obviously not. Anyway, I cannot seeme to get the jump connections replicated for manual control and with the PTO switch at close monitoring. I have tested all the relay leg contacts in the relay base but cannot find 12v. Is it supposed to have power or just contact points? Is the pto solenoid exposed?? I cannot find it.
I have mislocated my 6640 repair book!

 

[sotxbill]

Alright, I will look again. And and no, my tach is not working when cold.
Thanks.

I dont know if the pto safety relay uses the tach feed off the alternator or uses the "charge" feed off the alternator, but the book says its dependant on the alternator to activate the safety relay iirc... So .. if the engine stops, the pto is cut off and you then must turn off the pto switch off.... and turn it back on to get the safety relay to kick in.... while the engine is running.

 

[agsnow]

I dont know if the pto safety relay uses the tach feed off the alternator or uses the "charge" feed off the alternator, but the book says its dependant on the alternator to activate the safety relay iirc... So .. if the engine stops, the pto is cut off and you then must turn off the pto switch off.... and turn it back on to get the safety relay to kick in.... while the engine is running.

I am getting no PTO action after all electrical diagnosis. I have proper relay connections and 12+Volts on the pto manual pto switch.
I have looked at the solenoid switch and a loose pressure switch connection was found but do no think it was interactive. the attachment location cannot be spotted at the moment...
PS. the medium green wires in and out of the pto switch cannot be traced directly to the solenoid switch.. Not sure where they get exchanged....