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Discussion Starter · #1 ·
(Also posted in Honda-Tech)
I've done a lot of research but maybe I didn't use the correct words as I don't know the name for some parts (Gray boxes bolted to the chassis under the dash).
Here's the thing... I recently bought a cheap car and put an engine in it... the wiring inside of the cabin looks like a mess. When I hooked up all of the wiring my main relay isn't clicking, instead I hear a buzzing sound but I don't think it comes from the Main Relay.

Civic Hatchback 94 - Manual Transmission (P06 ECU)
D16Y7 engine
Y7 Dizzy converted to OBD1 (Re pinned the sockets)

Main Relay
Fuses are all okay... including #13, #18 and the one for the ECU and Back Up. I opened the Main Relay and it looks fine... I jumped 1/5 (KOEO) and also 1/7 and the fuel pump primes both of the times. I even tried a second main relay and the issue persists.

I re-did the main grounds, I.e:
-Chassis to valve cover
-Chassis to bracket on top of the tranny
-Thermostat... I even ran a cable directly from the thermostat ground to the negative terminal of the battery.

There are 2 wires cut loose from the ECU but as far as I know both of them are for Vtec and I'm not using it, so I "guess" it's okay to leave them as is.
The ECU is good, I know it isn't burnt. The only thing that I haven't checked so far is the ground from the ECU wiring.

I've attached 3 pictures:
The first one shows a blue wire from a gray box that is T'ed to a green wire... I don't know what that gray box is supposed to do, neither the T'ed wire.
Also, there's a red wire hanging around that is grounded to the chassis using the bolt from one of these gray boxes.

The second one shows a gray socket with three wires. (Black with silver dots and two red wires with silver dots as well) One of those red wires is t'ed with a white wire... Those three look all messed up.
At last, theres another two cables hanging around. One of them is "white/red stripe (white looks kind of beige), the other one is Green/red stripe (Green looks like mint color).

Is there anything else that I should be checking?


Love the Civic
1,817 Posts
Red wire in first pic looks like a fan switch instead of relay replacement at some point.

The red and white wires, have you traced them and followed where they go? Could be old alarm wiring or subs.

The green and silver wire in the ecu is supposed to be org/white, it was for the vtec motor previously in the car or running under the whatchful eye of your p06. Since youre running notec, I would not concern yourself with it until youre ready to tidy it up after you repair it.

I think your car had an alarm and vtec and youre seeing the left overs. Check the link for some pointers in a direction, I recommend finding where the other end of these wires goes, if nbo where pull em.

How to Install a Car Alarm - 5th Generation Honda Civic EG

4,112 Posts
I hate fixing other peoples garbage wiring. Every time I've ended up just replacing the whole under dash harness with a known good one. Definitely look at alarm wiring diagrams and try to work your way backward.

Also I see your main relay is not bolted to the frame. It needs to be grounded if I'm not mistaken.
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Reactions: robgoof

Premium Member
5,819 Posts
It looks like an old alarm wiring that's been cut out.

Is that red wire that grounded going to anything?

The white/red and green/red wires I think are for either the dome light or power locks. I can't remember

Blue wire that's tee'ed no clue.

That green plug I think is for the starter relay. What color are the wires in it?
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