Harry Ferguson
12-14-2015, 11:26 AM
While I have the dashboard off, it is a good time to see about hacking an ambient temp display. When the 825i is turned on, for a few seconds the top center of the dash screen displays "-188* C/F". So the unit is capable of displaying outside temp but John-Deere didn't order that. Two possibilities are: It won't work without proper software and the label says this unit has v1.3, OR: it only needs a thermistor hooked to the correct terminals. If the latter, this should work. Any of the unused terminals on the dash unit might be the one, but connector C-26 terminal D looks likely and it is right next to coolant temp. A thermistor would likely connect between term D26 and F26 gnd. Are thermistor sensors standard? Maybe the dash will "see" the sensor and turn on the temp display? Also, there will need to be a signal to select F or C, which might entail grounding or not grounding one of the remaining unused terminals (maybe S25?). But we see that battery voltage to terminal K-26 selects diesel function, so perhaps B power to another terminal selects C / F. I am reluctant to start jumping battery power to random terminals without knowing which one lets the smoke out. This dash unit is made by Pricol in India and the numbers are visible in the picture I posted. Does anyone know anything helpful about this panel or the hack I am attempting? If this same dash panel is used on something else besides J-D 825i, maybe a temp sensor and schematic is available. I plan to open up the panel and look inside for more clues, but wanted to post what I have in case someone has info.