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Old 12-29-2020, 07:59 PM   #13
Scooby Guru
Member#: 108051
Join Date: Feb 2006
Chapter/Region: Tri-State
Location: NY
2005 TickingTimeBomb
Jr tuned TT Sleeved


Originally Posted by Cougar4 View Post
I'm not clear about what you used for the reference ground point when you read the .5 volts on one of the ground lugs. You need to check the connection going to the reference ground. I recommend you use the negative battery post as your ground reference point. I doubt the Main Relay itself is shorted but something it connects power to could have a short across it. Some of the engine related sections that fuse SBF-5 supplies power to do draw a fair amount of current so the .5 volt drop you saw may just be due to wire losses, but the voltage drop does seem a little high for that.

The factory manuals not only show what the wire colors are going to each connector pin it also shows connector colors and where the connectors are located in the car. There is no better reference manual available that I know of. It also shows the ground wire connections in a separate section.
I have the negative on my multimeter hooked to the negative battery post..

I unplugged the brown connector on the main engine harness and the black and red wire is seeing .6v now.

I checked on the chassis harness end. So I traced that back to the black plug under the driver's dash side next to the blue plug that also shows continuity between the b/r wire leading to engine harness.

So with both unplugged I have continuity and no voltage good so I know that section of harness isn't an issue..

That black plug under dash with small Black and red wire is showing .616 volts I believe it's a ground since it connects to ground under the hood.

It appears to run through the dash harness to the ecu. Appears to be pin D1 and D1 or b137 1,2 if looking at oem manual. I found a pin out online for free but seems to be missing pin function b137 pin 16

Anyhow I'm gonna unplug the ecu and see if I'm still getting .616 volts at the terminal plug under driver's dash. If the volts goes to 0 I'd guess the issue would be in the circuitry on the ecu.

If it doesn't I'm assuming something else in line is causing the issue. Suck working without a repair manual. Especially electrical stuff. So far they seem to match the colors of wires going into each plug well so it isn't to bad to track down.

I did use the kengilbert manual to rebuild my engine and transmission. But the wiring has different pins for the 04-05 sti
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