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Back story: 04 RX-8 6spd GT. Got the car in February as a roller. Installed the engine and trans over the weekend. In the process I cleaned all ground points and ensured the grounding points were secure.
When the doors are opened, the door ajar indicator light does not illuminate on the cluster and the interior lights do not come on. When the ignition switch is turned on, nothing happens. The only working components are the parking lights and hazard lights.
Battery is good. Connections are secure and terminals are new. I have good power (source voltage) at the fuse box under the hood. 120A main fuse looked good but I swapped it with another known good one I had just to be sure.
Moving inward I have no power at the fuse block in the car. I checked the wiring under the dash and it all appears to be connected. I didn't see any broken wiring. At this point I'm fairly stumped. Looking for any advice or direction. I do have the factory wiring manual so we can use that for reference as well.
Last edited by mazdaverx7; 04-12-2021 at 05:42 AM.
I pulled the BTN fuse and I have source voltage on the (as I face it) left side pin. I checked the pins for voltage on my Brilliant Black 04 and the only difference is I have 1.2V on the right side pin on the black car and 0V on the right side pin in this car.
I have no voltage to the 15A room fuse. No voltage to any of those fuses in the drivers side fuse block actually.
12V power comes from the battery to the 120A main fuse, then to the 30A BTN fuse, and then to the 15A foom fuse which is the pcm power supply. So that’s narrowing it down for you ... if the 120A main fuse is good and has power on the output side, then it has to be the wiring between there and the BTN fuse. Otherwise it has to be between the battery and 120A main fuse.
There should be two wire terminals and a wire with white connector plug that come from the battery + and are attached to the 120A fuse and engine bay fuse box per the pics in the link below and down further in another post below it circled with the red oval, please review and compare. It seems like one of those three connections must be off.
Maybe the white connector isn’t plugged in, but could be one of the others. or possible the terminal connections are reversed. My memory is a bit rusty on those connections, but you can see in the pic linked below the difference between the terminal shapes and the position they should be in.
Thank you for the information! I can tell you that the routing in my fuse panel is identical. I will ensure both terminals have source voltage.
The white connector is plugged in and secure but perhaps it has pin fit issues or a bad or missing pin. I hadn't considered that until now.
I'll have to look into the wiring diagram and see how many things that room fuse powers.
I did previously repair a cut wire at the ignition switch and two under the fuse panel. Apparently someone was trying to bypass the immobilizer and make the 4 port engine run using the 4 port engine and the 4 port ecu with the original key to the car. I'm guessing they found they were not getting anywhere so they tried to bypass the immobilizer by running a wire from the fuel pump fuse and the starter fuse to the ignition switch directly. I removed the wiring which was crude and repaired the wiring under the fuse block in the engine bay and I repaired the wiring at the ignition switch.
sorry, got confused when you started referring to another vehicle and misinterpreted your reply
if you have power at the BTN fuse and the fuse is good, then the issue is the wiring from there to the ROOM fuse on the interior fuse panel
you can try a jumper wire between them to see if that solves it, but sounds like another wiring modification issue by whoever had it prior to you. So maybe you missed another one under the fuse panel.
well there’s also a side node between the BTN and ROOM fuses that feeds the other interior fuses. So the wiring from the BTN fuse is definitely the issue. still think I’d try to jumper power to the ROOM fuse first to assess if it’s just that branch or not.
Team, you were 100% spot on! I used the factory wiring diagram i have and the traced power diagram you provided and traced the power circuit from the BTN fuse to the room fuse. It should have connected to a light blue with red tracer on the opposing male harness under the dash. The connector it was plugged into was wrong. I found the correct connector was plugged into a different connector. I swapped them and BAM!
Thank you! I'm glad it was an easy fix. Someone had definitely been in there and im not sure why. Doesn't matter I guess. Its fixed now and I can proceed with the restoration with my sons.
04-12-2021, 05:38 AM
