# 1991 D21 5 speed trans. electrical plugs.



## jmacf14 (Aug 28, 2009)

I have a 1991 2wd nissan that is an automatic. The auto trans went out, and I'm converting it to a 5 speed, because I have all the necessary parts already (from another 1991 2wd that is wrecked), and I can't pay the $1200 for a rebuild. This just costs me blood sweat and tears. My problem is that I don't want to change the entire wire harness out, and am afraid I will have to. The auto trans harness doesnt have the 2 plugs for the 5 speed trans. I know 1 plug (on the 5 speed trans) is for backup lights, but what is the other plug on the trans for? My manual says its for an o.d. switch, or top gear switch. Anyone know exactly what that does? Will it be detrimental if I don't connect it? The only other thing is the clutch switch, witch I'm not real concerned with. Any advice or help is appreciated. Thanks!


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## zanegrey (Dec 5, 2005)

first if you are going to a five speed from auto you do not have to change the wire harness.

on the manual trans the switch to the front is reverse switch and the one to the rear is the neutral indiactor switch..

i have that auto trans for sale..used but in good conditon ..
pm me for price if interested...


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## zanegrey (Dec 5, 2005)

please post ur location...


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## jmacf14 (Aug 28, 2009)

Thanks for the response. So Im going to leave those connectors on the man. trans. empty and should have no issue, right? I plan on wiring in a toggle switch for the backup lights. That will be great if so, because it is a pain in the rump swapping the harness! Already a job as is with the different brake pedal, clutch pedal, master and slave cylinders, as well as the plumbing for those. Then there is the speedo cable, and shift linkages, as well as other stuff. It's a chore, but saves me alot of coin. Thanks for the offer of selling your auto trans., but I will continue with this. Thanks again.

P.S. I live in Oregon.


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## zanegrey (Dec 5, 2005)

the reverse plug should have its own plug on both versions...


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## jmacf14 (Aug 28, 2009)

Here is an update for future reference for anyone interested. This job took about a day and a half by myself, with some good help from my 11 year old daughter. It may not be worth the hassle for most, but saved me $900. I had a "donor" truck (my truck that was totalled) that made it worth while. I picked up a great truck off craigslist for $300 that had a seized engine. Unfortunately it was an automatic, and the trans was starting to go also. I didn't want to spend the $1200+ to have it rebuilt. 
So here is a list of all componants that needed to be added or swapped on the "new truck"; swap brake pedal, add clutch pedal, master cylinder, plumbing, and slave cylinder(kind of tricky not bending the tubing!), speedometer cable, remove auto trans and fluid lines, swap driveshafts, swap transmission crossmember, and exhaust bracket that bolts to crossmember, swap floor pans to allow for shifter, cut hole in carpet, remove column shifter and linkages (easier than swapping steering columns). Also the flywheel needs to be swapped for the clutch to be added.
A couple of side notes; there were three harness' that will be left disconnected on the steering column from the shifter, there are also three plugs left disconnected by passenger side inner fender from the auto trans. One of these is the neutral safet switch (the only one with 2 wires) that needs to be bypassed to allow the starter to engage. I did this with a simple jumper wire with 2 spade connecters. Unfortunately the harness doesn't match up for the backup lights to function, so I am currently tracing the correct wires in the truck for that, and will fassion a harness out of the harness from the "donor" truck so I can have backup lights without having to remember to flip a switch on and off.
Removing the old brake pedal was a pain, because I had to remove the dash to get to it, as well as vent ducting. I was able to barely squeeze it past the steering column (after I unbolted and dropped it 2 inches, not removed). Take good care to mark, or photograph where the harness' go in the dash for the instrument cluster.
Anyway I thought I would add this in case somebody else ever tries the same thing.


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## zanegrey (Dec 5, 2005)

*not a bad father and son gig...*

i have done that swap .

it is a lot of work but it sounds like it was a great bonding for you ,your son and one of the best freind a guy could have ..that is a nissan truck..


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## jmacf14 (Aug 28, 2009)

One final note, I traced the wiring diagrams I found on autozone.com, and found the wires in the correct harness' from the auto trans, and my old 5 speed harness, and was able to solder the plug from the auto trans to the harness for the 5 speed, now I have functioning backup lights. She's running GREAT!


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## zanegrey (Dec 5, 2005)

bravisimo ....


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