Hello HT,

Ive been working on a swap now for awhile. In college so its taking forever. Anyways, today I decided to hook up a battery and check out the wire tuck me and my friend did a year ago. We only tucked the chassis harness behind the front fenders and moved the fuse box into the glove box. From what I remember we mainly just extended grounds. My engine harness is only half connected (No head on engine).

Now, When I hit my brakes with key off my battery light, and brake light illuminate.

As well, my temp gauge skyrockets. If I plug ecu and hit brakes it will not sky rocket the gauge but fries ecu. Same symptons when I turn on dome light and headlight switch.

Battery is not fully charged either.

I have a degree in Automotive/ High Performance Motor sports so I am capable of fixing issue. I just have no clue where too start. Or if this is common.

Key on is just battery light. Until I hit brakes etc etc.

I appreciate all opinions and help.

 

What wire harnesses? Been doing a lot of wire cutting and splicing?

Does the same thing happen if you beep the horn?

 

It sounds like you ran the ground wire for your brake switch into your engine harness if you still haven't tucked the whole harness try tracing the wires from the brake switch and see where they go. If you tucked that part already test resistance from your brake switch connector to your temp sensor connector for the dash gauge their is more than one temp sensor normally what are you swapping in.

 

Its the factory 92 Civic Si harness. Had a d16z6 going too a b20v.

About a year ago I tucked the chassis harnesses.

On the pass side I extended chassis the harness to under the fender and relocated my fuse box to the glove box, I extended the grounds, headlight, turn signal, fan and relays.

On the drivers side I split the harness right out of firewall where it originally comes through into two harnesses, one harness goes to under the fender for the windshield washer fluid, headlight ground block etc. The other goes into engine bay which get hooked into engine harness, power steering rack.

It seemed like a really simple tuck so I didn't worry about it until now. Just got fresh bottom end in, hooked up engine harness which I ran through factory location onto block. The head side of harness is just chillin. I hooked up a weak battery to be safe and found out that when I hit my brakes, combo switch, or dome light, my gauge
cluster goes wack and smokes the ecu after a few seconds of brakes too floor or any of above.

The horn makes my relay click with key off, ko it lights battery light but no relay, on run it does nothing

 

stock engine harness

 

I looked at some wiring diagrams and it seems like everything that is going haywire uses Junction Conn C417. Thanks for your input. It is greatly appreciated!