8970A CCM question

juniur · May 29, 2019

Working on a 8970A. Issue is a F312 fwd solenoid
circuit fault. Found the fwd solenoid wires naked
and the insulation melted. Replaced the solenoid,
still have the same code. When I go into mode 7 to
energize to solenoid it does not magnetize. I can
unplug it and read battery voltage, with a load in the
circuit ( light bulb or solenoid) I don?t read any
voltage.
I?ve check the wiring all the way back to the
connector under the cab. Has anyone seen one of
those solenoids short and mess up the chassis
control module?

Larry NCKS · May 29, 2019

I don't have the electrical manual for the 70A series. However, I'm assuming it. like the 70 series electrical manual, would have flow charts for diagnosing fault codes. You likely need to obtain a 312 diagnostic flow chart for your A and follow it. There are more steps outlined than the ones you've mentioned to pinpoint the cause.

jbirnsch · May 29, 2019

Have you checked for a short to chassis ground in the harness? If no short then it would be possible to burn out the driver in the CCM module. I have attached the wiring diagram and flow chart for troubleshooting. I have also seen corroded wires show voltage without load then one you apply a load drops to 0 volts.

Ag Express should be able to fix it.

juniur · May 30, 2019

Yes I have a complete set of manuals. I?ve followed
the flow chart all the way to the step that says
replace CCM. I mentioned checking the wire back to
the cab connection. What I meant was I?ve checked
it for continuity from pin F back to the solenoid
connector. Checked it for short to ground. I?ve also
load tested the wire.
Ive had components damage modules on truck,
auto, and other equipment before. Ive never had to
replace a CCM on one of these tractors before.

juniur · May 30, 2019

talked to a former ford/nh tractor dealer service manager ( we dont have a dealer locally that works on the big tractors any more) he said the fwd solenoid causing damaging the CCM is pretty common. when i removed this one from the tractor i found that it had been fixed by ag express once before. has the previous owners name and the F312 code written on the side of it. im going to send this one to ag express and get it fixed.

jbirnsch · May 30, 2019

All of the modules in our 8970 have Ag Express stickers on them. Probably burned the MOSFET on the board that drives the solenoid.

8970A CCM question

juniur

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Larry NCKS

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jbirnsch

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juniur

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juniur

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jbirnsch

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