Note: the '7747 and '7783 at least use the same method of preventing overload to the A/D circuits--a 10k resistor seen in the following images ("103").
Peter of DIY_EFI indicated the following which is verified by the image below: ----------------------------- +5 | | / | \ \ / 3.6k \ software controlled \ \ switch / o \ \ | | | 10k |------------------------/\/\/\/\---o to A/D, etc. | / \ / \ 348 / \ | | o terminal on ecm
C11 (MAT) looks to be like ----------------------------- +5 / \ / \ 2.5k / \ | 10k |-----/\/\/\/\--o A/D | | | | | o terminal on ecm