Trouble shooting a JD 6620 header control w/ DAM

It is that time of year to make necessary combine repairs. Last fall I think I might have cut my beans relying primarily on the plastic skids under the head and the lift provided by the compressed nitrogen tank. Worked well, just cut beans too low and got into the dirt once in a while. Probably not the best for the life of the plastic skids. Combine is Dial-a-matic and head is just older style "header height". There is an adapter between the header wiring and combine wiring. I need some trouble shooting ideas????????

I do know about pushing the little pins on ends of the hydraulic / solenoid valve. It does work - push the pin on the left header goes down / push the pin on the right header goes up. Manual header control lever in cab works as it should as well.

Can I hot wire with a jumper the solenoids one at a time to see if they work properly?

Can I test the combine wiring/controls at the plug by making electrical contact between certain pins in the plug?????? Anyone know what each pin or color of wire does ????

Since the combine has Dial-a-matic, does the DAM knob in the cab have to be set on a certain setting ( 0, 1, 2, 3) for the older height control system on the head work?

Can I add Dial-a-matic to my older style head? Older style head has the micro switches mounted up by the reel operated by the long rod. Dial-a-matic box is mounted down by the sickle directly on the rod operated by the skid plates. Can the Dial-a-matic box be easily added to this rod??

I might add that the hydraulic oil temperature light did come on a few times last fall. Probably takes at least an hour before it comes on. Stop and it goes off and stays off for half and hour or better. These were warm days.

Any other ideas appreciated. Thanks.

I can provide a quick answer, but not a lot of detail. We purchased a 7700 Deere combine in 1981 or 1982. The combine had the automatic header height control on the base machine and also on the 220 flex head that came with the combine. As I recall, both the combine and the flex head were manufactured and bought as model year 1976. We tried the automatic header height on the combine by itself and it just did not work very well, so we ran the head and machine just as you said you ran yours. A year or two later, we were able to add the Dial-a-matic control to the base machine and I think there may have been some hardware added to the flex head, too, but I just do not recall for sure. It really worked well after that. When we moved up to a newer machine with the nitrogen accumulator, it really smoothed out the automatic operation of the header height control!