I rarely post, but this problem got me.

Car- 1999 Civic Sedan (Canada)
Engine - 1999 Integra LS (US)
ECU-OBD1 LS
Problem - I just finished the swap a few days ago, but I cant figure out why my alternator is pushing our 17v, which is way too high. I thought it was the voltage regulator inside the ALT was bad so I swap it out for a new Alternator and it still does the same thing. Thought it was the ELD so i swap in a US Fuse box (with the ELD) wired it up, tested the ELD, works correctly, 5v when nothing is on, drops as I start turning stuff on.

Funny thing is if I unplug the alternator connector the voltage drops down to 14.4v. I could run like that but I really want to figure out the problem.

Does anybody know which wire (coming from the ecu) tells the ALT to engage? i know its either the WHT/GRN (ALT C) or WHT/RED (ALT FR)wire.

Your thoughts?

 

white and red i believe iis the alternator control signal.

 

been looking around WHT/GRN is Control. read a few troubleshooting procedures and they all talk about the WHT/GRN wire.

Checked all wires and made sure there is connection and no short, everything checks out.

Big white wire is showing the alternator output
Blk/Yel- is battery voltage
Wht/Blu (to cluster charge light) - is battery voltage
Wht/Red (ALT FR)- shows 5volts
wht/Grn (ALT C) - not sure how to test this

starting to wonder if its the ECU...

 

so i de-pin the wht/red wire from the alternator connector. Alternator still pushes out 17v

 

borrow an ecu & replace it. if fault gone then u know wat to do, otherwise check wiring as per service manual