First, what does the 5th gear switch exactly do anyways? After my swap, I got the backup lights wired properly, but I just couldnt figure out how to hook the 5th gear switch w/o shorting the ignition fuse. (the switch from the transmission has only two pins comming out... NO clue how to wire the 5th gear switch back). Any ideas?

 

That switch on a USA car has four wires.

Two wires are of one color, and the other two are of another color.

So one circuit is made up of a set of colors and the other circuit is made up of the other set of colors.\

On a series four non turbo car, you has two RED and two GREEN.

The GREEN wires are the fifth gear swith circuit. They SHOULD have blade connectors and go to wires on the chassis harness that are blade connectors also. One of those on the CHASSIS side of the connector will be Black (going to gnd) and the other Black with a Blue stripe (BL). This circuit should NEVER have power on it although with a meter you probably could read voltage being backfed from the ECU on the BL wire.

All the fifth gear switch does in life, is put a GND on a pin in the ECU which in turn causes the Split Air Solenoid on the ACV to pull in and feed split air to the catalytic converter.

The other two wires are RED and go to the reverse lights. Those should be bullet connectors that mate with bullet connectors on the Chassis side of the harness. One of those wires on the chassis side of the harness should be Black/Yellow and will have 12vdc on it when the key is to ON. The other wire on the chassis side should be RG or red with a green stripe and goes to the backup lights.

To be absoulutly correct, the BY and RG are on the ENGINE harness.

Same with the B and BL wires, they're on the ENGINE harnes.

Evidently you have the wires crossed at the connections of the switch and are putting a gnd on the Black/Yellow wire popping the fuse.

OR the switch is shorted internally or/??????????

 

I did something unique for me. I actually read your post this time.

The switch on the left side of the transmission is the reverse/over the top switch and should have four wires. Two red and two green.

The switch on the right side of the transmissiion is the neutral switch with two wires.

I explained how the four wire switch works and connects on the other post above.

IF you have but a two wire switch on the left side then it is possible that that transmission is a JSPEC transmission which only has two wires because they don't use the over the top or fifth gear switch. They only use the reverse.

IF you find four wires on the switch on the right side of the transmission, then the switches are installed *** backwards.

 

ok, thanks so much, you're always of great help
Sorry I forgot to mention I just did a succesful JDM swap (with N370 ECU, S5 N/A wiring harness)lol... so yes, the engine and trans are JDM. And yes, there are only two pins comming out of the reverse/neutral switch just like you said, and I have the reverse lights hooked up right and working.

So, not having the 5th gear switch wont make any difference correct?
thanks again

 

None. It only activates the Split Air Solenoid on the ACV and ONLY when fifth gear is selected. It will not cause the catalytic converter to go to hell in a hand basket nor will it effect emissions testing (they never go into fifth gear during the test anyway).

 

Thanks again! On another note, could you also give me your advice/opinion on IF it would be worth my time to port my stock wastegate or not...

Link to me asking in another post with no success:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/porting-wastegate-623182/

 

I would NOT.

 

=(

 

Don't get me wrong, I did my research... and I know how porting your wastegate help reduce or advoid having overboost and boost creap, but it seems like it is mostly a S4 problem. I wasnt sure if other people reccomend doing this on a S5 just as much as on a S4. I was thinking of maybe getting a warning boost guage, so I know as soon as I pass a certain psi (10 in my case), in order to avoid blowing my engine...