I am wondering if anyone has insight as to what is actually "inside" the console module, According to my book, this is an AT100073 "digital display" which houses the warning lights. When putting the key to the "on" position, I would assume that these are supposed to illuminate. They don't, and never did. Nor has there ever been any noise out of the buzzer. I had the panel off when I was checking the heater fan switch, and there is just a big connector plugging into the assembly. All the warning lights are driven from this. I wasn't sure if there were individual bulbs/etc. or what may have happened to this poor abused machine over the years, but having some of these "functional" would be nice. The replacement part is selling for +- $1200 (about 2x original retail). I don't think so. Might this just be a glorified harness/display, or is there some sort of logic/etc. in this module? I can fix (or probably construct a new) just about anything electronic, from tube AM radios to complex digital circuitry. I can manufacture PC boards at home if needed. There were a few "splices" noted in the wiring area, that I have a feeling were not "factory" performed. I noticed this when repairing the heater core and installing my new heater fan. The mixing valve (for heater core temp) was gone/bypassed as well, leaving the control cable dangling. BTW, the $16 80W electric fan from Amazon worked just perfectly in place of the rusted/seized OEM fan. Blower control works great, and a good air volume. Thinking about adding this to my list for winter refurbish. Not a lot of info on the module in the books I have. It would be nice to have overheat warnings/etc. and possibly the buzzer.
You have to be between "ON" and "Start" to illuminate the bulbs. That is the bulb check position.
Not a single light, anywhere between ON and Start. Starts and appears to run just fine. Not sure if these are bulbs that all died, or if I have to take a look at what the previous owners may have done. I suppose I could see if there is active voltage with a meter on one or more pairs feeding the display panel.
Mg might correct me if I'm wrong, but some JD "monitors" of that era were activated by the ignition switch grounding the monitor in that in between position. No ground and the monitor will not function. I probably messed that all up, but the gist is that it's not an intuitive wiring system, so you may have some simple external circuit issues that you'll never find without a wiring diagram, or way more work than needed. Nothing wrong with wiring all the gauges direct, and eliminating the module also.
That would be correct. Terminal "G" of the ignition switch supplies a ground to the "E" terminal of the Logic Module 5 pin connector which arms the Logic Module and then grounds then activates the lights for bulb check. Make sure you have a good ground connection between the "E" terminal of the Logic Module to the "G" terminal of the key switch all the way to ground.