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Sat Nov 23, 2002 6:57 pm

I've got a alternator with the external regulator on it, I think they were 73, 74 only. My question is; when I turn the key forward to the on position, the idiot light goes on like it should, but when I start the car, the light does not go completely out. It does dim a bit but it is definitly brighter than a "glow", but not as bright as before i started it. The light used to go all the way out, obviously. Where should i start looking for the problem, the alternator or the regulator? I did re-wire the alternator to regulator conection (3-prongs) but this did nothing. The the regulator is also grounded well. Any Ideas??
thanks.

Sat Nov 23, 2002 8:57 pm

What does a VOM tell you voltage wise???

And has the battery gone dead???

are the lights still bright at night??

If so, the regulator may be getting old

( I like the sealed up Motorola style, but have/do run both the other being Bosch box)

or the overall output (amps) weaked by most common the brushes getting worn/short and or the commutator dirty...

It is very easy to take the top part off the alt where the 3 rpong plug in is and undo the screws and lift the white assembly/brush holder out to check.... (note the one spade will slide out throough the white piece and the other two will come off with it)

Now with a light, look inside the alt and you will see the commutator part of the armature and you can clean them with a pencicl eraser or a fine piece of wet/dry sandpaper... and you can look at the brushes and maybe pull on them and stretch the springs for better contact pressure....
(You may be able to locate some at a alt/starter repair shop...)

Re-assemble and see what gives.... if the light still glows a little it can also just be chocked up to some resistance in the old wiring... I drove a 73 for well over 10 years with a dimly glowing light at night and never had any trouble...

(Though no Big output stereo or amplifiers)

I even changed regs and did the above and it would be cool for a bit and return... my voltage (rev's up for cut in speed) was 12.95-13.5V and I never bothered to check the amp output as I never had a dead battery (due to the alt not putting out enough anyway!)

Anyway, that is my expereince and I see that alot on other cars too... so????
Tinker away and worry another day..... good luck!

Sat Nov 23, 2002 9:27 pm

thanks keifernet
I checked the voltage across the battery with the car running and it was only 10-12 depending on if the lights were on at any rpm. I turned the car off, set up my voltmeter to ground and to the fat red wire off the alt, and at first it read virtually nothing, and then blip the throttle and the volts jumped to 13-14, where they should be, but at the same time the voltage at the battery was only still 10-12. This seems to me to be impossible seeing as how the fat red wire from the alt goes directly to the battery, I figured that they would read the same but no luck. I don't know where to go from here.??
thanks.

Sat Nov 23, 2002 9:45 pm

Well, the big red wire does not go direct to the battery IF you do indeed have the 3 prong stock alt with the V reg under the back seat... sounds like the Alt is putting out and the V reg is suspect/bad... If it is the solid state sealed flat "motorola style" if you unscrew it from the rocker channel and look at the back side and the gel is all melted bubbly looking then it is shot. or if it is the Bosch metal box style you can undo the piece of tape holding the cover on and look inside at the guts and see if it looks smells burnt up.... I think is probably is, unless you have some other wiring troubles...