Alternator Whine With New Head Unit

[Ben Freeman]

So I recently changed out the stereo head unit on my [new to me] '88 FJ62. I've replaced stereos on every vehicle I've owned, so this wasn't an unfamiliar process for me.

The unit that was in it wasn't original, my guess is it was installed in the mid-90's. It had a tape deck, but wasn't working well enough with a tape/aux adapter for me to listen to music from my phone.

Anyway, I replaced it with a fairly inexpensive Boss head unit from the local auto parts store. Everything works fine except that I am getting some alternator whine through the speakers when the truck is running. The pitch goes up and down with the engine's rpm's. I tried cutting the ground [black] wire and grounding it to the chassis. The unit still worked but the noise was unchanged.

I should mention that whomever installed the mid-90's aftermarket unit, cut the original harness and hardwired that unit in. However, there were two cables left unconnected from the original harness: the green and the white/green wires.

I've had a hard time finding an accurate wiring diagram for my '88 FJ62 online and am wondering if one of these two [unconnected] wires could hold the key to fixing my ground hum.

Any advice is appreciated!

 

[StarCruiser]

This is a problem I thought was consigned to history. Clearly I was wrong. Type in Car Radio suppressor into EBay and have a look at the array of low cost items you can try. First I would suggest an alternator suppressor. If that doesn't do it report back and we'll go for something else.

Good luck with it, it shouldn't be too hard to stop (famous last words!)

 

[Ben Freeman]

This is a problem I thought was confined to history. Clearly I was wrong. Type in Car Radio suppressor into EBay and have a look at the array of low cost items you can try. First I would suggest an alternator suppressor. If that doesn't do it report back and we'll go for something else.

Good luck with it, it shouldn't be too hard to stop (famous last words!)

Thanks! I'll give that a try and report back.

 

[Ben Freeman]

[update]

I grabbed a couple of these noise suppressors, they were sold in pairs, on Amazon: https://www.amazon.com/dp/B00I8QQ3WC/ref=cm_sw_r_cp_apip_6xQxF2naqrtUi

I installed one on the constant power wire and one on the accessory power wire and... no more hum!!!

Thanks for the advice @StarCruiser!

 

[StarCruiser]

Woohoo… That's a result there Ben!
Glad it worked.