For our trucks, specifically the obdI versions, 94 and 95, are the engine wiring harness and transmission wiring harness seperate, or are they one?

Also, on the 94 they have just an upstream o2 sensor, but do 95+ have both a upstream and downstream?

Thanks -

 

I think the wiring harnesses are all one. Difference would be between manual, and auto trans.

Downstream O2 showed up with OBDII in 96.

 

OK thanks. Just wanted a little jnfo for some future projects