Ford Repair: Amp Gauge showing Discharge., altenator, solinoid

Question
I have a '74 Ford 1/2 Ton F100 PU. With ignition OFF the Amp Gauge reads -30. Start truck and it jumps to 0 and works it's way back to -30. Won't go above 0 anymore.  I replaced the battery today, no luck.  I've had the truck since '78, replaced the alternator in the 80s.  Any ideas appreciated. Thanks much.

Answer
Mr. Cadero,

If it is discharging, you have a short in your charging system somewhere. It could be a battery cable, the altenator (to check, with vehicle off your batter should read 12.4 volts and when started, your battery should read 14.4 volts if your altenator is working right-use a volt meter to check) or the cable from the solinoid to the starte. Just be cause a cable looks good, does not necessarily mean that it is good. If they are very old, I recommend changing them. If this does not solve your problem, please contact me again and I will assist you further. Hope that this helps and good luck.


Ken