Would an alternator be the cause of this?

[RollingsFarms]

My lights on my truck keep blowing out one by one. First it was the daytime running lights(typical of GM), then it was a reverse light, now a headlight. Could this be the alternator overcharging?

 

[k0ua]

My lights on my truck keep blowing out one by one. First it was the daytime running lights(typical of GM), then it was a reverse light, now a headlight. Could this be the alternator overcharging?

Easy way to find out.. Just get out your multimeter, and measure your charging voltage with the engine running at about 2000 rpm. Should be 14.5 or less. And it should taper off a bit as the battery charges up from a fresh start. Many are about 14.2 and taper down to 13.8 or so. If you see anything above 14.5.. you have a problem. And yes the alternator/regulator, (most are built in) could easily be a problem

 

[Diamondpilot]

Easy way to find out.. Just get out your multimeter, and measure your charging voltage with the engine running at about 2000 rpm. Should be 14.5 or less. And it should taper off a bit as the battery charges up from a fresh start. Many are about 14.2 and taper down to 13.8 or so. If you see anything above 14.5.. you have a problem. And yes the alternator/regulator, (most are built in) coule easily be a problem

I agree 100%


Chris

 

[Xfaxman]

I bought a cigarette lighter voltmeter.

Plug it in before I start the engine, to monitor the condition of the battery when the glow plugs come on.

 

[k0ua]

I installed a permanent one.

 

[JJZ 109]

I'd have to double check, but I think my Lemur OBD monitor also checks on voltage. I'm sure that many other OBD types will do this also, in addition to the many other features on them.
I know for sure that the Aeroforce Interceptor gauge in my bucket truck does.

 

[jwstewar]

A bit of a hack, but if you have a Prodigy PIII brake controller, it will give you the voltage going to it. Since it should be a direct line to the battery, it should reflect what the alternator is doing. I've used it a couple times on our Suburban to verify it is a battery issue and not an alternator issue when I didn't necessarily trust what the factory "analog" gauge was saying.

 

[ThomasH]

Easy way to find out.. Just get out your multimeter, and measure your charging voltage with the engine running at about 2000 rpm. Should be 14.5 or less. And it should taper off a bit as the battery charges up from a fresh start. Many are about 14.2 and taper down to 13.8 or so. If you see anything above 14.5.. you have a problem. And yes the alternator/regulator, (most are built in) could easily be a problem

Unfortunately a multimeter will not show any voltage spikes that the alternator is putting out, as multimeters average out voltage to give you a fairly stable number. It takes a scope to see spikes, which can and will do lots of electrical damage to lights, the PCM, etc.

 

[HHR]

Unfortunately a multimeter will not show any voltage spikes that the alternator is putting out, as multimeters average out voltage to give you a fairly stable number. It takes a scope to see spikes, which can and will do lots of electrical damage to lights, the PCM, etc.

Peak voltage adapter will work with a digital multimeter to show voltage spikes. They are hard to find though.

 

[schmism]

Peak voltage adapter will work with a digital multimeter to show voltage spikes. They are hard to find though.

standard feature on any fluke ive owned. course thats a $150 meter not a free one from Harbor freight with coupon.