Driving into work this morning, the Airbag light came on and the needle in the Voltage gauge began to swing from N to L in "Normal', with the headlights and dash lighting dimming and returning to normal as well. The 'swing' oscillates around 3 cycles per second and there was no difference in driveability of the truck; no loss of engine power or surging through the drivetrain. Oddly, after about a minute and a half of this weirdness, the Airbag stopped illumniating but the condition continued. At idle, the voltage oscillation does not mainfest; it is present at any other throttle position. I did not have a meter or time to diagnose voltage swings before coming inside.
Aside from a Kenwood receiver, the truck has no aftermarket lighting or additional components such as a CB, Amp, or Fog lights.
I suspect the issue is with the Alternator or the voltage regulator. What say you?

 

 

Before dropping new money on an alternator, obviously measure your voltages and all that, but also clean up your battery cables and contacts REALLY well.

If you do need a new alternator, see if yours is 3G and if not, upgrade. I'd also recommend upgrading to the 130A version because they aren't much more expensive, and it gives you lots of upgrade room in the future if you do decide to put in a better stereo or anything else that strains the system.

 

Before buying ANY parts...

1) Smell the ADM. If it stinks, read this caption:


(phone app link)

2) Inspect/clean/repair the battery terminals. NOTHING electrical will work right if they're trashed.


(phone app link)

3) Don't guess. If you suspect an alternator problem, read this caption:


(phone app link)