Got a 1995 LS 400 and recently noticed a weird electrical humming sound at exactly 40mph and only at that speed any ideals what this is?

 

Welcome to CL.
A bit more information would help, where is the noise coming from?

 

The noise started when my voltage regulator was going out sence then I have replaced the alternator and fixxed that issue but still get the electrical humming sound at 40mph any ideals?

 

Do you have like any aftermarket stereo stuff? Amp? Subs?

 

Welcome to Club Lexus.

Did it hum prior of just recently with this issue? Is there aftermarket audio equipment installed? Is the audio system on when this occurs? Checking the grounds to the audio gear would be my suggestion..

Alternately I would suspect a tire wear issue but a hum may also be a drive line/tranny noise.

 

No aftermarket radio, speakers, or sub all original. The humming started when the voltage regulator and alternator was going out didnt make it before hand. Anything else regulates the voltage in the car other than those? Also got brand new battery. Also have brand new tires all around were put on last summer.Also tried turning off everything when the noise started air,radio,lights still made sound hear it really good when inside the cab with windows up and everything off.

 

if the radio is off, even an electrical hum wouldn't be audible

my vote is something like a wheel out of balance, a wheel bearing, an idler bearing or other pulley or bearing driven by the engine.

The only other thing that comes to mind is the speedo making noise.

 

now mentioning the wheel when i hit 60mph around there get little shimming in steering wheel gets worse when i break at that speed.