Guys I need some major help! Electrical

[Mike Bucher <mbucher@domain.elided>]

Matt,
> 1977 IH Scout II, .. battery gauge  jumps back and forth... when I don't
have my lights ..is fine....when I have my lights on and my heater it goes
lower and it
makes my lights get brighter and dimmer. ...install a CD Player ...it took
even more power away ...the radio ...cut off and on during a cd or radio
station. 

>Is it the alternator:  more than likely.  Need more amps to run all of the
equipment.  Larger alternator (more amps) or replace the brushes in the
existing alternator.

>wires:  could be, where did they hookup the CD player.  You may need to
run a larger gauge wire to supply voltage to your fuze panel, getting too
much voltage drop on the existing wire.  
> check the ground wires?  With all of the usual rust you get on an old
vehicle, your vehicle/chassis ground can get weak or non-existant.  

>Where are the ground wires?  I have pickup and Travelall, someone else can
help on the Scout ground.  Sometimes there is a strap from the engine to
the firewall.

>no noledge of electronics.  
Sounds like time for a "learning experience".  Get a Volt/ohm meter and
start measuring voltages at the various instruments (radio, CD, lights,
alternator, battery, fuze box) under various load conditions (lights only,
lights & heater, etc...) at both idle and high rpm.  Write things down so
you can make sense of the numbers and conditions later. 
Also measure resistance (ohms) from the chassis of the CD & radio to frame
of the Scout and from the Scout frame where the radio & CD are grounded to
the negative side of the battery.  These two readings should be very close
to the same number and be a very low number.

You can get an inexpensive volt/ohm meter for $10-15 from Harbor Freight or
your local autoparts .

Mike