Originally Posted by JimmyL

Still could use some help with this one. I can't find anything on the 123 Service cd relating to the tach, pickup, etc..... Then I throw in the uniqueness of the '85 model and searching wasn't conclusive.
My tach is inop. Always has been. I have replaced the computer module, as stated above. I finally sprayed off the front and rear of engine, and found the tach sensor up front, and some type of sensor, under oil filter housing on drivers side of bell housing.
I was going to remove them, clean and inspect them, take readings, etc..... But during my searching, somebody raised the possibility of one of those being utilized for the cruise control, which actually does work. Perfectly in fact.
So, I want to trouble shoot my tach without rendering my cruise inop. Make sense?
Fuse for overload protection relay is not blown.
#1 - is the sensor up front where the rpm signal originates?
#2 - what does the sensor on the bell housing do?
#3 - does anyone have this circuit diagram that could scan it and post, or cut and paste if it is electronic?
#4 - what senses the vehicle speed for the cruise system.

Thank yall in advance.