Bypassing computer controlled/electronically switched tractor functions

[Dunno]

Hello,
I have recently acquired a tractor that is an early 90s vintage that has a computer that controls, I guess, a lot of things. It also has an electronic dash that controls lots of things too, but that is not working right now. Tractor starts and runs well and drives, but 4WD is controlled by an electronic push button on the dash, and I think it is not working. Can I bypass electronic switches and use toggle switches to control things in general, and the 4WD in particular? Thanks.
Best regards.

 

[grsthegreat]

Those buttons more than likely control power to a relay. The relay does the real switching. Relays fail all the time. Need to do some troubleshooting. Just swapping button for toggle wont bypass the relays.

 

[grsthegreat]

Bypassing the controller…… man, thats alot of reworking of the system. The controller interconnects everything. Especially if its fuel injected.

 

[Dunno]

Grs,
I know things are pretty interconnected, and with 4WD on , it might tell the computers something about it being on. The engine runs like a dream right now, so even though the dash is not lighting up, the engine still purrs. My thought was just to get the front tires turning with the maybe inop electronic dash switch. As long as I keep the oil, water, and hydraulic fluid levels proper, I Don’t think I really need the dash to tell me anything. AC works, horn , lights, wipers, etc, controlled by rocker switches or knobs. Tractor shop manual detailing electric arrives soon. Thanks.

 

[TractorTech]

What model do you have? 4WD controllers on Fords usually controlled auto 4WD. When the controller is not working the 4WD is engaged all the time.

 

[Dunno]

Hi TractorTech,
1992 Ford 8240 SLE. With the tractor I received another electronic dash, looks new, still in the plastic bag. On the bag is a printed sticker that says ‘For 8340 with 4WD problems’. The 40 series are all very similar. The tractor has low hours and is in really great shape so I plan to keep it, spruce it up, and fix all the issues it has.

 

[TractorTech]

I believe that the 4WD is the same on the SLE with the solenoid being on the transfer box. Power to the solenoid turns the 4WD off, no power turns it on.
I think, but not sure, that the dash only displays the gearing, but doesn't have anything to do with the powershift. Of course, if you want to do any calibrations, you need the readout, but if you have the other dash, then you are good.

 

[Dunno]

TT,
Thank you. I will start to explore with a multi meter when I get the manual. Not sure why someone bought the new dash but didn’t install it. I’m also thinking that the machine had electrical problems early which is why it doesn’t have a lot of hours. I read everything I could on them, so I’m aware of the issues with the early white roof models.
Best regards.

 

[LouNY]

I like the 4wd being failed or power off to engage. As the Fords, NH and CIH do.