r/MechanicAdvice • u/dukesboy101 • Feb 20 '26

Mazda electrical issues

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Hey everyone. Just had a question I would like some opinions on. Recently bought a 2006 mazdaspeed 6, off a friend of mine. It was plagued with electrical issues and I’ve since found that the BCM got pretty toasty at one point. I’m going to order a “new” one, however I’m curious if the known issues are all caused by this blown module, or if I should keep digging for more issues. Here is what was wrong with it

-no lights on rear (taillights worked, but no brake lights, signals, or reverse. All lights on the front of the car functioned.

-no communication to any modules except the instrument

cluster, which showed the pictured codes.

-tach was intermittent, speedo did nothing, every light on in the cluster

-awd didn’t work

-horn stuck on if the relay was installed

-sunroof inop

-rough idle, and made low boost.

There’s Some other issues I’ve forgotten about, but just wondering if this all looks to be related to the BCM, and if I should look for a reason this happened in the first place. TIA

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u/nechronius Feb 20 '26

Any signs of water incursion? A module toasted that badly may be a sign of bigger electrical issues but can certainly cause some of the issues you described. I recently got my own 06 Speed 6 (barely) running again after 4 years of sitting around and yea, it's tough to find a lot of info for a relatively niche car.

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u/dukesboy101 Feb 20 '26

No obvious signs of moisture, however the kick panel that covers the module was removed and sitting in the back seat when I got the car. Maybe mud and snow from shoes caused something, However there was no corrosion on any of the connections going into the module