i've put an SE engine in an 85 GS (see thread for details: https://www.rx7club.com/showthread.php?t=796342), which as you all know was a 12A powered car. i have the harness from the ecu to the engine. it appears intact and it looks pretty decent. so my question is, where soes the harness come from for the oil pressure sender, coolant temp sender, the two main relays, and the SE fusible link block and if someone can post some pics of it that would be great. i've got the engine in and i'm just trying to get all of the wiring figured out. as a note, i do not have the SE fusible link block yet or the two main relays behind the left strut tower so i do not know the wiring colors for either. do those mentioned harnesses have connectors that one could just unplug and remove? i would assume that the fusible link block does not but i was thinking that maybe the oil pressure sender, coolant temp sender, and the main relays have a harness that can just be plugged in.. thank you guys in advance for your help.

 

i'm at another stand still. i removed the old N249 ecu out and installed the N304 ecu today and when i was pulling the old wiring harness through the dash, i noticed that it was tough to pull through. further investigating lead me to remove the glove box. thw wiring harness goes clear behind the blower motor assembly and behind the vents and somewhere into the dash i dont know what to do about this. i looked at the fsm but it of no help because it isnt detailed enough for wha ti am looking at. i would really appreciate the help. i can post pics if need be.

i would also like a picture of the acv relay. i have a pile of relays for the SE and i want to make sure i use the correct one. i was also able to locate the main relays in my pile so that puts me that much farther ahead.

 

if you can,get the dash wiring harness [main ] from the SE. Thats the easy way.
Your gs harness does not have the necessary plugs to power up the ecu.I did this swap about six months ago only took an afternoon. Good luck with your GS-E

 

how much of the dash harness do i need and what exactly does it connect to dehind the dash?

 

if the complete SE main harness is available use it. runs from fuse panel behind dash to ecu ,but also out driver side firewall to fusible links,headlights,across front of car and back to ecu harness.Its not that hard to pull the dash and the harness is just plug and play.

 

Your also going to have to change fuel pump, lines and pick up

 

yeah..i just need to know where this harness runs behind the dash and what exactly it connects to so that i know how much of or if all of the dash to remove when swapping in the SE harness.

 

Dave,

The harness runs from the driver engine bay (coils, relays, etc.), goes under the dash near the pedals, and then runs to the ECU. It is the 'Front' harness that you are looking for. There is another harness under the dash called the 'Instrument' harness.

You can see all the things that the front harness connects to by looking at the wiring diagrams. The wire color will be followed by [F] to indicate that it is part of the front harness.

You might be able to fish the 12A harness out and the SE one in with the dash in place, but it is sure a lot easier to do the work with the dash out (although the dash can be a pain to get in/out).

 

thank you for the response! that gives me a better idea of how to go about attacking this. seems that all i have to do is fish the harness out of the engine bay and through the dash and out through the right side of the firewall with the rest of the harness. so, this new SE haness that i need will power the ecu?

 

I will be shocked if you can fish the harness out from behind the dash. Its strapped to the firewall in several places that you can't get to without the dash removed[first hand knowledge]

 

thanks for the heads up. i may just unbolt the dash and see if i can get my hands behind the dash while its loose. if that doesnt work, i'll remove it

 

The harness that goes from the ecu to the drivers side will come off if you take the bolts off the blower and pull it out some (I had to remove AC hoses at fire wall) and it will give you better access to the harness.There is no plugs,some of the wires go to the ignition and fuse box others to main relay and acv relay.I'm doing this swap to my 79 sa and I'm still trying to figure out where this wires will go,already got some but still working with the wiring diagram.Hope this helped some.

 

i've almost got the dash completely out. i have the entire SE harness (thanks Doc) and i am just going to swap that in place of the GS harness. hopefully this will go smoothly. one connector at a time, lol. and i'm still not sure if i'll be able to keep my current heater controls...