Hi All, recently my 2006 V8 Limited started making a strange rumbling sound from the passenger side dash, in addition to an electrical whine through the speakers. Even the electric brake booster noise was amplified. My first guess was a failing alternator; however, I think the issue may be related to the headunit. The headunit has begun to restart randomly and the speakers have also stopped working. Only when resetting the battery will the speakers power back on. Is this an electrical/grounding issue from the headunit or something else? Also by chance, my steering has begun to feel verrryy heavy. I'm not sure if the issues are related, or if the truck is just falling apart at once. I intend to flush the power steering fluid today and look at the intermediate shaft. Merry Christmas to me!

Thanks!

Pull the fuse for the headunit and see what happens. I think you have a bunch of issues all at once though. But just eliminate things one at a time.

I pulled the two radio fuses and sure enough any rumbling and electrical noises disappeared, leading me to believe that there is some grounding issue with the head unit. I'm assuming something has just shaken loose and I'll be doing a deeper dive this week. I also hit the intermediate shaft u-joint with some WD-40 and that seems to have fixed (temporarily) the stiff steering issue.

Bringing this to the top...

When it rains it pours. Two weeks ago my car also went into limp mode and pulled a P2445 code (secondary air injection pump stuck open). I have a bypass kit so was lost as to why this happened. I pulled the negative battery terminal overnight, wiped the code, and voila! No issues in over 300 miles since....until...

Recently when putting the key into the ignition and trying to start, nothing happens! No crank (one click MAYBE), very dim to no power to accessories, etc. Yet, it would ultimately start after a few attempts. I checked the battery and it was still reading 12.6V when off. Based on some research I was lead to believe it might be a key/immobilizer issue. When I use the non-chipped key everything works fine?? Any ideas with this latest issue?

Test your alternator.
How to Test a Toyota Collora Alternator is Good or Bad Using a Multi Meter - YouTube
TEST YOUR ALTERNATOR TO MAKE SURE IT’S GOOD. #shorts #youtubeshorts - YouTube

You also might have a bad alternator cable.check your terminals

It doesn't make sense that it's immobilizer related if you are losing power. You read 12.6v at the battery but what about inside the car, like at the accessory plug, when the key is turned to start? You should have very little voltage drop between the battery and that plug. How do your battery terminals look? All 4 contact points should shine. This is my quick check for loose/dirty connections, turn the headlights on in a place you can see them, try to start the car while watching the lights. If they dim or go out but eventually come back after letting go of the key then you have a bad battery or bad connections somewhere. If you monitor with a meter that's on the battery at the same time (need a helper) and the voltage doesn't drop much then it's a connection somewhere, usually the battery terminals.

TY both above for the suggestions. I'll give them a go this weekend. Good news is we bought a new Grand Highlander so the pressure is off a little bit to get this sorted out.

Good ending to a headache for sure - I've been chasing a complete shutdown of the side and rear window defrost on my 1995 SR5 - For a long time -