1991 Toyota Pickup
3.0L 3VZE, A/T, 2WD
Japan Mfg
1 Ton chassis for a Winnebago RV

I would like to ask if there are any resources that provide a physical route of circuits that could be used with the schematics to make tracing electrical issues a little less difficult.

I am trying to track down some wiring issues in this vehicle – specifically associated with the ignition circuit. I do not have the actual wiring schematics for the 1991 model year, but have a complete FSM for 90-95 model years with many schematics. I understand that these may be similar but possibly not exact between the years, but is very similar to the 91 layout.

Although not an extensive electrical background, I am fairly familiar with understanding the information contained within the schematics and power source flow information. My problem is that the many schematics fail to identify information of another circuit (splices, etc) that has common/shared wiring of the circuit you are interesting in.

Just one example of this is on the “IGNITION” circuit schematic goes from connector (IH1) to splice point (E24 – igniter/ignition coil) and does not show the splice point (E18 - injectors +12v) as shown in the “ENGINE CONTROL” schematic. There are many of these between different schematics.

I understand that it is not practical to have every schematic show complete shared circuits and the items left off of a given schematic may not be considered part of that schematic’s circuit. So, I would like to know if there might be something that could make a schematic more informational as to the actual circuits route or location of the wiring..

Thank you for your assistance.

 

The official Toyota EWD (wiring diagrams) does 'roughly' show the location of loom harnesses and approx locations of connectors and components. I also seem to recall the OWD (overall wiring diagram) at the rear of that manual does show - a bit indirectly - where each circuit does and how (sort of) it interconnects with everything on that fuse, for example.

Toyota online I believe still have them available if you can't source elsewhere.

 

Thank you for the information. I have been trying to combine the following information to help me determine circuit wire routes:
- Overall Wiring Schematic
- Individual circuit schematics
- Splice Point / Wiring Connector / Component location sheets
- Engine and Cowl wiring harness images (from Amayama)
- Any other info I can locate from internet researches and forums

Using these resources, some of the actual wiring routes are quite intuitive to determine. However, some other information is not as apparent and the resources I am using do not provide a conclusive answer. Thanks again.