William --

Before you do open-heart surgery, confirm that ALL the fuses have good, clean, and tight connections. Retension (translation: bend) the clips, as needed, to grip fuses tightly. Be certain the fuses are of the proper amperage rating, and are in good condition. Clean the fuse clips using a green Scotch "scrubbie" pad—they're very abrasive, but non-conducting. Also clean the fuse ends. I used a touch of synthetic grease on the clips to inhibit oxidation (which uncreases resistance, creating heat, creating more oxidation, creating more resistance......and so on).

My various 240's do exactly as you've described (all have the voltmeter added), and I know from experience that it's simply voltage drop across the fuse connections. Cleaning 'n tightening the fuses eliminates most of the voltage drop, and also eliminates most of the voltmeter instability.

Don Foster (near Cape Cod, MA)

Thew guage will fluctuate a bit as different loads are applied, but 12 volts with blower on is too low. Check at the battery wiyh a volt meter to verify guage accuracy. If guage reading is correct, chargeing voltage is too low. Clean and check battery cables, alternator to block ground wire, belt tension, brushes/voltage regulator, battery condition. The brushes are checked by removing the voltage regulator on the back of the alternator. The regulator is aprox 1"x2.5" and is held to back of alternator by two screws. Disconect neg batt cable and remove the screws. Remove the regulator and inspect the brushes. Good ones protrude from the plastic housing 1/2" or more. If length is dramatically different from one to the other or they are very short, replace the regulator. Also check voltage drop between large wire at back of alt and + batt cable, and engine block and - cable. To measure voltage drop, start engine and conect a digital volt meter from alt large wire to + batt cable. Reading should be less than .1 volt. Repeat at neg cable to block. Blower and lights should be on for this test. If reading exceeds .1, there is a cable or terminal problem. Hope this helps.