Here is what's going on at the ammeter: At IDLE... lights off=slight discharge...lights on= very slight discharge. Then, at 2000 RPM...lights off=slight charge...lights on= slight discharge. Now, what I've done up to this point is new alternator, new voltage regulator, cleaned ground contact at the firewall for the volt.reg., cleaned ground at the engine for the neg. battery cable, cleaned and dielectric greased the 3 bulkhead connections. This problem just came out of nowhere. Tried a brand new volt. reg. tonight and it was fine for about 3 minutes and the problem returned. Another side note is when you're driving at night with the brights on, after a few minutes, the lights will flicker on and off. No problem if you drive with the dims on. Thanks for the help.

pull the alt field wires and pull the reg triangle plug. with some jumper wires: jump fire from the alt batt stud to the nearby field terminal (either one). jump fire to the top terminal nub in the reg. connect the side reg terminal to the other alt field terminal. see how it acts. the HL switch is bad

The'69 volt regulator doesn't have the triangle plug. It has a screw on the right side which has the green wire going to the one (and only) field terminal of the alternator. The left side has a slip-on spade with a double wire from the wiring harness. Could you explain how to do the same with this system?

take the blue and green wires/terminals off of the reg & keep the blue wire terminal from dangling loose & touching anything (its hot). pull the green wire off of the alt field terminal. jump 12V to the "ign" reg terminal that the blue wire was on. run a jumper from the "grn" reg terminal that the green wire was on out to the alt male field terminal. start it & run it at a fast idle & see what you get. if it stays good then there is an open or intermittent open in the blue or green wire circuit(s). If it does not stay good then it has to be the alt or the reg & you've checked their grounds. then take the green wire off of the alt & run it at a fast idle with lights/accessories off & jump 12V to the alt male field terminal for 3 seconds max & see if the ammeter pegs to full charge (grab a helper to sit in the inside & watch the ammeter plus you can likely hear the eng slo slightly if the alt kicks in). this full fielding tells you the alt is good & all that is left is the reg. you might pull/check the alt brushes if still bad on the full fielded test. does this reg have visible wire wound resistors on the bottom side of it? EDIT have a jumper between the reg and alt in the first test before you jump 12V to the ign side of the reg

Had a similar problem in my 67 coronet.. Turned out to be a loose connection at the starter relay on the firewall..

By loose it was snug, but not tight.. Try tightening the nut that holds the cable on the relay... Chased that one for a few months..

Well, drove to the garage before I got your most recent reply and this is what it did: Lights Off: At Idle the ammeter flips from slight charge to mid charge, At 1000 RPM flickers at slight charge, At 1600 RPM constant slight charge. Just by turning on the dim lights the ammeter discharged at Idle and slight charged at 2000 RPM. But, with bright lights on it discharged and discharged more with higher RPMs.

After this test, I hooked everything back to normal (I did put a brand new GREEN wire on from the regulator to the FLD terminal on the alternator) and got these results: Lights Off= discharge at Idle and slight charge at 2300 RPM. Lights on= constant discharge.

Didn't see Minivans comment until I got back, but I'll check that next time am at the garage. Thanks.

lets cut right to the chase & full field that bad boy for 3 seconds. that'll tell us if the bottom line in any charging situation (the alt) is OK or not & we'll go from there