1980 Diesel Pickup eating batteries

[wmasscaddy]

There is a 5 amp (brown) fuse marked "RADIO" in the fusebox that powers the red alternator light and the instrument cluster. If that fuse is blown, the alternator won't charge. It will blow if there's a short anywhere in the cluster.

[Fatmobile]

Oh, good one, I didn't know that.
Good idea to check the fuse first if there is one.

[greg lousy]

My caddy would kill my battery until I found the GP relay was sticking on.

mine too - This condition killed my old battery, then a brand new one after a few times connecting a charger with this circuit closed. Quick enough that the guy at the store was in disbelief when I returned it ("unlimited" warranty... right?)

.... definitely worth the quick check - GP wire will be warm to the touch with a good battery - or will show a reading on a voltmeter with a bad but not dead battery

[supersisu]

Hey Everybody, I think I've solved the problem:

Do you know what kills batteries faster than anything? NOT PLUGGING IN THE ALTERNATOR!!!! Duh. Maybe it was the working in the cold and snow, maybe I didn't plug it in all the was and it fell out, who knows?

All I know is that when I got the time during daylight hours to take a look, the alternator was not plugged in. Seems to be working fine now (at least regarding electricity, please see new topic "1980 Diesel Pickup Stalling" for the latest problem.

Thanks to everyone that chimed in, all very helpful.

[Fatmobile]

There are some very cheap digital voltmeters available.
I like the VDO volt meter in the center console but the digital ones are a good option.
Really an important gauge to have.