I have a 2004 f-150 that makes kinda a grinding noise or high kinda pitch noise and the battery light comes on and the dash lights go a little dim and it only lasts for 15 to 30 seconds. It don't do it all the time, Sometimes once a week then its good for another week or so. Took it to Firestone and they said it needed a new battery and altenator. I said if your sure put them in. Worked fine AAGAIN FOR 4 OR 5 DAYS AND THE NOISE WAS STILL THERE. tOOK IT BACK TO fIRESTONE AND THEY SAID THE ALTERNATOR WAS PUTTING OUT GOOD. I SAID CHANGE IT WITH A NEW ONE. THEY DID AND ALSO CHANGED THE IDELERthat keeps the belt tight. Drove it for a few days and the same noise. Did some research on my own and it sounded like it could be the IWE Solonoid. I took it to a Ford dealership and he said that it sure sounded that way. So they chaned the Solonoid out and blew out the vacuum lines and I left and drove the truck for about a week or so and be darned if it did not make the same noise. I have spent so much money on this truck all for nothing. Now they want to replace the starter, Another $360. It starts great, Never had a problem with that. What do you all think? I would really like any suggestions what you all think.
Thanks and sorry about the typing mistakes.

 

Does it make the noise at idle or when moving? If when moving, it might be the IWE solenoid or a vacuum leak causing your 4WD to partially engage. Since you have a new battery and had 2 alternators put in with the noise still present, it's probably neither of those. When it makes the noise, put it in 4 HI and see if it immediately goes away. If so, that gives you somewhere to start.

 

It makes the noise when I drive and the battery light comes on. Sometimes once a week. I did have a new IWO solenoid installed and told them to blow out the vacuum lines, But did they blow them out? Who know's. Thank you for you answer. I was at work the other day and at break time went and started my pickup and the battery light came on and the dash lights dimmed a little and about 15 -20 seconds later the light went out. But I don't hear the noise unless I am driving.
Thanks again

 

you aren't running an aftermarket stereo or anything are you? Amps etc?

 

What brand alt do you have installed ? sounds like you may have 2 different problems.

 

No aftermarket components installed, Except the auto start the dealer put in that only works when it feels like. The alternaters Firestone put in came from Napa I believe.
Thank You