Could it be that it's still the regulator? That this variance in charging voltage might be a sign that it's going? I'm measuring key off power usage correctly.

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

I'm not exactly sure what is happening but may be some of the electrical testing links given in this thread (post #1) will help?

Refreshing the alternator on an OM617

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

I don't think so. A regulator is a solid state device with no moving parts and do not wear out. They only go bad if you exceed it's rating in voltage and temperature. If it's an intermittent problem, I'd be more inclined to look at the 3 prong connector and the spring contact (in the alternator) to the regulator. Scrape clean those contacts and make sure they are not loose. You may have to put tension back on the spade lugs by squeezing them with pliers.
Leave you DVM hooked up while you drive and see what the charge voltage is at all times and report back.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Start back here:

If you pulled the fuse and the draw went to a measured 600 mA, then put the ammeter across the window heater fuse connection (meter takes the place of the fuse). In theory, if everything else stayed the same, you should still have a 900 mA draw on that circuit. That would at least verify there was a high draw condition on that circuit.

It doesn't explain the phantom 600 mA that were there then disappeared yet.

If there is a high draw on the window heater, then replace the fuse and remeasure the overall draw at the battery. It should be incrementally higher than the draw at the heater fuse if the heater is the only problem. If the heater is the problem, you've at least isolated the circuit causing the draw problems.

Well, I just replaced the fuse and measured the draw and it was still zero. As for the charging issue, I think it's the plug. I measured 12.3 V with the engine running and I wiggled the plug and it jumped to 13.6 V. Still not sure what's up with the phantom draw, though.

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

Alright, again, still not sure what happened to the phantom draw, but I've figured out why I measure zero draw-my ammeter doesn't read below 10 mA. Here's what I'm using: http://www.sears.com/shc/s/p_10153_12605_03482141000P?prdNo=3&blockNo=3&blockType=G3

I'm starting to think I had left something on when I was measuring that pull.

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

Your meter can measure milli-amp. Stick the red lead in the V/ohm/ma hole and the DC A scale to 200 m,, not 10A.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Back in the old days when we used Analog Multimeters, we would always start at the highest voltage or amp settings on the meter. That way, if the voltage or amperage was very high, we wouldn't blow the instrument.

If you get a reading in the lower end of the scale, you'd check it's value and switch to a better range for a more accurate reading. Work your way down one step at a time until you get a good reading.

I figure, the same kind of precautions couldn't hurt when using a DMM.

Measure voltage across the component.
Measure resistance across the disconnected component.
Measure current inline with the flow. Or, with inductive (probably only works on AC) current measurement.

Using Ohm's law, if you have any two of Voltage, Resistance, or Current, you can calculate the other one. Current (I) = Voltage (E) / Resistance (R). Manipulate equation algebraically to isolate desired term.

Forgive me if I'm telling you something you already know. But, hopefully, if it wasn't known, then this might help.

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Codifex
1981 240D ChinaBlue (Got her running with a donor engine.)
1983 300DTurbo w/sunroof.
1984 300TD manual sunroof. (Electrical Gremlins)

I guess I can try measuring across the fuse, but I don't know if I'll get anything. I'm not too worried about it. I cleaned the 3-prong plug and everything seems to be working just dandy now.

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

NOT ACROSS THE FUSE!!!!!!!!!!!!

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Oh yeah, that makes sense, lol. Where else can I try measuring if I don't get anything at the battery?

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition