Odd electrical issue

Lunar-Eclipse

Okay, I tested again with different ground points and I'm getting 2.4V with the car turned to "On" and 3.8V with the car running.

I also tested both the "cigar lighter" and "power socket" connections at the kick panel and I'm getting 2.4V as well. That's a lower reading than yesterday so I think the problem is getting worse.

It looks like the problem is further upstream. According to the electrical diagram in the service manual (PWO-2) the next thing up is fuse block/junction box M1 (PG-112)in the engine bay. It looks like M1 is a single chunk of fuses that can only be removed as one piece. Looking through the window at the top of the fuse block it doesn't look blown. Do I have to replace this whole thing to be sure?

The electrical diagram breaks down the M1 fuse block further (PWO-3) but it's beyond my understanding of electrical diagrams.

Any suggestions?

SouthArk370Z

Looking at PWO-3, the "FUSE BLOCK (J/B)" is on the left side of the driver's footwell, not in the engine compartment. "M1" refers to the connector used on the Fuse Block (J/B). The fuse is a 15A in position 20 (see lid of fuse block for physical location).

Since both the cigarette lighters are "dead" and they share a common ground, I'd take a closer look at your ground wiring if you have 12V at FB(J/B) fuse #20.

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Lunar-Eclipse

And the weirdness continues...
I went out there again to test the voltage at the engine bay fuse box and it was reading 12+ volts. So I went back to the kick panel and stuck the voltmeter probe in there and I got 12+ volts. Then I went to the cigarette lighters and tested and got 12+ volts.

So I'm thinking one of two things is happening here... either there is a loose wire going into the back of the kick panel fuse box OR there is a fuse/wire that is failing once it heats up.

SouthArk370Z

Plug something with an LED on it into one of the sockets and wiggle the wiring going into the fuse block. If the light is steady, then it's not a loose wire.

While you have the LED plugged in start tracing the wire(s) from the fuse block to the sockets, wiggling the wires as you go. If the LED blinks, you've found the problem.

You may have dirty fuse contacts. Pull the fuse, clean the contacts on the fuse, and re-install.

Not very likely. An "intermittent fuse" is a rarity in my experience (other than contact problems as above) and, unless you were putting a load on the sockets, heating doesn't enter the equation. But not impossible.

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Lunar-Eclipse

I wasn't getting 12V at the kick panel. I was getting 2.4V and I was grounding my probe against the bare metal or the firewall.

SouthArk370Z

Ah. That's sounds like you weren't getting power to the Fuse Block. IIRC, power to the fuse block for the sockets comes from the ACC output of the IPDM (next to the battery), but would need to go through the drawings to be sure.

Where on the fuse block did you take your measurement? If you were not on the "hot" side of the fuse contacts, you would be seeing stray voltage.

Grounds can be tricky, especially on modern cars. Try to find a place where other equipment is grounded and use that. Make sure you have a spot that is free of paint/varnish/grease/&c.


I don't think the HU is the problem. You probably knocked something loose when changing.

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Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma

Lunar-Eclipse

I was measuring from the right side of the socket. The side closest to the front of the car.

I'm pretty sure the other contact provided no reading. But don't quote me on that. I've looked at that kick panel like 30 times today.