Silverado electrical problem

:banghead: :banghead: :banghead: I have a 2002 6l 4x4 extended cab truck. I have changed the Altinator twice and the battery once. The problem is when driving and the RPMs reach 2000, the voltmeter on the dash drops from 15 to around 12to13, the head lights and dash lights dim. The diming lasts from a couple seconds to a couple of minutes as long as the RPMs stay around 2000. If the RPMs drop below 2000 to volt reading returns to 14to15. All connections are clean and tight. any ideas as to what's going on?

I have been told that the volt meter should anly read around 13. Is this true?:banghead:

Thanks for any help.

I would take it to an auto shop and check alternator. There should be no reason for your truck to do that. Autozone can check it for U free of charge.

Just a thought, but how does the tension on the serpentine belt look?

I would like to share my experience with similar symptoms.

Symptoms:
a. Dash lights and radio were on the fritz. Radio was sounding like it was skipping even though I was listening to FM. Dash lights were randomly coming on. Seemed electrical completely.
b. Idle engine radio and dash lights were fine and operated normally.

Diagnosis:
a. Whip out multimeter and getting 14.4 or so off the alternator.
b. Getting 12.6 off of top battery posts (New battery Feb of 06)
c. Getting 1.2 - 3 - x.x off of the side threaded mounts for truck.
d. Upon removing the side threaded mounts I noticed the positive connection had some corrosion coming off of it.
e. Removing the positive connection revealed massive corrosion under the rubber seal to protect against this.

The problem all along:
I blame myself because when instaling new battery in Feb of 06 I didn't tighten the positive connection tight enough for the teeth to notch into the new battery connector to make a good connection. If you don't do this there will be a small gab that will not make the connector to the battery sealed and moisture will get in.

Lesson learned: Make sure to give enough torque on the battery connectors when installing a new battery for the connector teeth to dig in.

Funny huh?

Mine does the same thing every now and then. Anyone else on here noticed this problem with theirs? Everything on mine is ship shape as well just never thought too much of it to dig and figure it out, just wrote it off as a nuisance thing....

I had a electrical problem on my 2000 Silvy and it turned out to be the ground strap between the engine and firewall, it was hooked to the bellhousing bolt and was very loose. Check it for the heck of it and see.