I swapped a 3.4 from a 99 AT Tacoma into my 95 MT 4-Runner. What should I do with the portion of the harness that has the transmission sensor and solenoid connectors? Should I just leave it or cut it off? I'd like to remove the excess but I'm not sure where's the best location to cut it.
The 1st photo shows the portion of the harness that I don't think I will need. The 2nd photo shows where it originates to the left of the oil fill cap.
Your advice would be very much appreciated.
Thanks!

 

I do believe 2 of those plugs in the first picture are for your o2 sensors. I would absolutely wait until you have it running before doing anything like cutting them off! And then, I would just tape them up really good.

 

Ha yes! O2 sensors...
Thank you very much!

 

Like vasinvictor said, you'll need to the two O2 sensor plugs but you'll also need the R (reverse, red-yellow for a 1997) and the +12V (black-yellow for a 1997) wires from the Park/Neutral switch, as well as the two lines coming from the 4WD detection switch.

The two lines from the Park/Neutral switch need to be spliced onto the plug from your 3.0's transmission for the reverse switch; this will allow the reverse lights to work when you shift into reverse.

Depending on your truck, the 4WD detection switch may not be needed, but the 4WD light on the dash will not light up without it (or a bit of extra work), If you still have ADD, you will definitely need those wires. Again, like with the reverse circuit, you'll need to splice the original connector from your 3.0's engine harness onto the 3.4's harness in place of the 3.4's connector.

As for the extra wires, I disassembled my harness and physically removed all the un-used wires, but I would not recommend that, there were a lot of them, and they were all very twisted together; I ended up having to cut them off at both ends and carefully pull the wires out. I would probably still route them down towards the transmission and just zip-tie them someplace secure and out of the way there.

 

I had seen the info on the splicing of the park/neutral switch on several of the swap threads so I was thinking of doing this and removing the rest of the harness. Based on both your input, I'm going to take the safe route and run the truck for a while before I begin hacking away. Assuming she fires up....
Thanks for your input. I wouldn't have ventured into this without all the valuable info you guys have shared.
Thanks again!

 

When I do swaps, I open the entire harness and de-pin and remove any wiring that is not used. I used a 1MZ from a Camry in my 97 Celica. tons of extra wires. This way everything can be cleaned and plugs can be replaced if necessary. and a new loom job at the end