need on multitester

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URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=126634
Printed Date: May 13, 2025 at 1:17 AM

Topic: need on multitester

Posted By: hoffmanp
Subject: need on multitester
Date Posted: March 20, 2011 at 8:33 AM

Guys, I am going to install a Water Methanol Injection (WMI) kit on my Toyota Fortuner diesel engine.

I have read the manual instruction and most of them I can handle it accept for the electrical wiring. I need to wire the WMI to battery wire on the ignition switch.

Can someone help me how to identify which one is the battery wire on the ignition switch using multimeter and how to wire them properly? Been searching on the internet for the fortuner ign switch wiring diagram no luck for me.

Here is the wiring diagram for the WMI kit. It's quite simple:
posted_image

Replies:

Posted By: kreg357
Date Posted: March 20, 2011 at 10:12 AM

The Fortuner is not sold in the states so I can't find any info listed but...
Set the DMM to the 20V DCV range. Connect the Black wire to a solid chassis ground. Probe the ignition
switch harness wires with the Red lead. There will be basically 4 types of wires found in that harness.
The proper ( Ignition ) wire will test 0V with the key in the off position, 12V (+) while the key is in the on position
and 12V (+) during crank.

There will be +12v constant wire(s) that have +12v all the times. Starter wire(s) that have +12v only during
engine cranking. And Accessory wire(s) that will have +12v only in the ACC and RUN positions, but not during
cranking.

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Soldering is fun!

Posted By: howie ll
Date Posted: March 20, 2011 at 6:00 PM

Switched ignition is probably BLACK/ red use your DMM. It will be the one that goes live on ignition and stays live during cranking.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.