3rd gen 3sgte wiring. I've searched all over. Options

[bccentaur3]

I understand that the wiring is almost all plug and play, but what I don't understand is what I do with the wiring harness. I've read things about the body harness and all this stuff and it has gotten me confused.

My question is, do I take the fuse box, relay box, and the wiring harness off the st205 clip and replace that with the 5s wiring harness?

Or do I just take the wiring harness from the st205 and use all the plugs and use the 5sfe fuse box?

And how do you take the harness off the bottom of the fuse box? I'm a bit confused here.

I plan on extending the wiring harness so I can tuck them and make them look clean as possible, but all this talk about body harness and which fuse box to use has gotten me confused.

Can someone please enlighten me?

[Silver94CelicaOw...]

I should probably do an actual writeup on how exactly to do the wiring. There seems to be alot of confusion over how it works, but I'll try to explain it pretty simply for now.




You need a complete ST205 engine harness, preferably with the fusebox(es) but definately with every connector in tact. The body plugs will plug into the car EXACTLY the way that a ST204 harness plugs in, so there are only a few hurdles to overcome at this point.

1.) Harness length. If you are using a RHD harness from a JDM vehicle on your ST204/AT200, you will need to extend the harness 28-30" so that it will enter the other side of the firewall exactly the same as the ST204 wiring. To do this, its easiest to cannabalize your old 5SFE harness for extra wires, since there are a few leads of insulated wiring for the resistor pack that you need to extend properly with the same sort of wire as the 3SGTE harness.

2.) Wiring up IC Pump Relay, Fuel Pump Relay, and Clutch Start Switch circuit. These three things are the only wiring difference between the USDM harness on our cars and the ST205. The main fusebox plug on the ST205 harness, "EJ1", will contain extra leads that are only for the fuel pump and intercooler pump circuit. Everything else is identical to the ST204. I used the BGB wiring diagrams for the ST205 and identified the leads that were extra and simply split them off before the fusebox, and rigged up two relays on the outside of the fusebox for these two functions. You would have to do something like this if you didn't have the ST205 factory fusebox (one that mounts to the radiator on ST205) for these functions.

You could also use the body harness wiring from an ST205 front clip, and just use the factory fusebox for the IC Relay and FP Relay. This would involve no wiring at all, other than the clutch start switch.


The clutch start function on the ST205 consists of three black wires on the 3 body plugs next to the ECU. All you need to do to rewire the clutch start is identify where the black wire is located on body plug "IJ1" from your 5SFE harness. Remove the pin with the black wire from plug "IJ1" on your 5SFE harness, and click it into the corresponding location on "IJ1" on the ST205 harness. Then join the three black wires to this one black wire that you just added to your ST205 harness, and the car will start.


EDIT: I should note that I've only done the wiring conversion on a ST204, however the AT200 wiring should be just as simple.


For now thats the best explanation I can give without photos. I can make this a step by step guide with pictures if you guys would like.

I've also tossed around the idea of doing these harness conversions for a very reasonable price for anybody interested, I actually like to do wiring as crazy as that may sound.




-Corey

This post has been edited by Silver94CelicaOwner: Apr 28, 2008 - 12:05 PM