[V8] Voltage on climate control head

[dsaad at icehouse.net]

Generally speaking, I think the CC head does a pretty "accurate" job of
measuring voltage - the problem is where it does the measuring. It "sees" its
own supply voltage - which is sourced through countless connectors and fuses and
many feet of wire. All wire has resistance - and the more current (or load) you
push through a wire, the more voltage drop you will see across it. The size of
the wire is also directly related. So - If you have a bunch of accessories
turned on you will normally see the CC head voltage drop. This may indicate you
have some resistive connections or other wiring problems if the voltage drop is
excessive. If you were to put a voltmeter on the alt output and battery posts
you should see a more normal voltage, with the alt post being slightly higher
since this is the source for the whole car and the battery representing a load.
If you don't see 13.8v on the CC head with all accessories off, you either have
a defective CC head (un-likely IMHO) or resistive wiring due to something like
corrosion somewhere.

The only way to tell for sure is to get out an accurate voltmeter and start
looking for trouble.

Dave



Quoting DasWolfen at aol.com:

> In a message dated 1/27/05 11:17:39 AM Eastern Standard Time,
> Speakoutprod at aol.com writes:
>
> > My understanding is that the voltage reading there is not all that
> > accurate.
> > I've done some testing on the digital readout and the "true" voltage
> > measured
> > at the battery -- and there can be a noticible difference.  Your voltage
> may
> >
> > vary.
>
> Just like any device it should be checked when you "know" your car is
> operating correctly then you "know" what it reads normally....then if you get
> an
> abnormal reading you have something to go on.
>
>
>  For example..... If your alt and batt tests with the car running shows 13.5
> volts but your CC head shows 12v, you know 12v is a normal reading for your
> car.
>
>  If you get a batt warning while driving down the road and you check the CC
> reading and its down to say....8 volts....well thats a pretty good
> indication
> your alternator isn't charging.
>
> Keith
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