1969 Westfalia Generator Light On

[jeb1978]

I've been attempting to fix a generator light issue on my 1969 Westfalia for a few days now. Late last year, the generator light starting coming on, first at idle, then all the time. The voltage regulator was replaced (with the newer Bosch solid state model), which solved the problem for a few days, but then the light was back on again. I don't recall offhand what kind of troubleshooting I did after this, but it eventually pointed to the generator.

Fast forward to the past week... I re-installed the engine with a Bosch rebuilt generator (GR15X, 30 amp). The generator light was on at first engine start, but went out when I bumped the throttle. It stayed out for about 2 blocks, and then came back on, all the time.

I checked the wiring, cleaned & replaced connectors as I found them, and now the generator light is on all the time at idle, and for the most part, stays out at higher engine speeds (it intermittently comes on at highway engine speeds, but it's consistent like at idle).

I've been through the following, in a somewhat rambling order:

When I measure the voltage from D+ to ground at the generator, at idle, it's very low, near 1 to 3 volts. Sometimes it jumps to ~14 volts at around 1500 to 1700 engine RPM, sometimes it doesn't. The voltage at the D+ regulator terminal follows this. The voltage at terminal 61 seems to follow this voltage reading as well.

B+ and the battery read ~13 volts.

I've done the no load test of the generator, and I read voltage as high as ~50 volts at higher engine speeds, where everything I've read says you should read ~35 volts.

I checked continuity between the generator frame and battery negative, and read 0.2 ohms, so that circuit appears to be OK. I also checked continuity of the terminal 61 wire to the dash and read 0.6 ohms (pretty long test leads). I haven't disconnected and cleaned the transmission ground strap yet, but I'm not sure I need to based on these readings.

When I'm in the engine compartment with the engine running measuring, I occasionally see a spark come from the generator, but it's intermittent, and not when I'm measuring anything (so I don't know if this is good, bad, or ugly at the moment)

The generator has been polarized, and spun like a motor when connected to the battery.

The engine starts and runs fine other than the generator light.

I picked up a second voltage regulator today at the local FLAPS in an attempt to isolate this part, to no avail, the generator light is still on at idle.

Any ideas what is going on or where else to look? I've searched through many topics here and at the other forum, but I've run out of ideas other than double double double checking everything I've done so far.

[vdubyah73]

If it was me, I'd check the fan belt first. It might be slipping a bit. Gens don't make much voltage at low RPM, they kick in up at higher RPM. If the belt is slipping, your fan isn't cooling fast enough either.

[Sylvester]

If it was me, I'd check the fan belt first. It might be slipping a bit. Gens don't make much voltage at low RPM, they kick in up at higher RPM. If the belt is slipping, your fan isn't cooling fast enough either.

Squeaks too.

[jeb1978]

Belt is tight, but I put my spare on to compare since I'm running out of ideas, same result.

I cleaned the transmission ground strap (although it was surprising clean), same result.

Interestingly enough, the generator light was on all the time today while testing. It would sometimes go off if I rev'd the engine up to 3000 RPM or higher, but then come back a few minutes later.

I did another no load test for voltage after this and got a high of around ~3 volts at the D+ terminal instead of the ~50 from the other day. I then tried to polarize the generator (again) and it spun maybe 1/2 a turn, and then stopped.

At this point, I gave up and removed the generator from the engine (with the engine still installed, it wasn't bad, only took about 30 minutes). I don't know what else it could be besides a bad generator.

The paperwork I got with the rebuild says it has a 12 month warranty, so I'm going see about exchanging it. The only problem is that I'll get another rebuilt one, which hopefully will work.

[jeb1978]

Well, I got another rebuilt GR15X under warranty and installed it tonight. Buttoned everything up, started engine, generator light on at idle. It goes out as I rev the engine.

Plus this generator came with a nice high pitched whine sound. It was pretty bad at first, but it's since become much quieter. I spun the generator by hand and with my drill, and it's not rubbing on anything. I took a drive for a few blocks to the gas station and back, and it seems to be OK, for now...

So I still have the generator light on at idle. It usually goes out around 1200-1400 RPM on the way up, and comes back on at the same time on the way down. Interestingly enough, it comes on solid around 1400 RPM, goes out for second, and then comes back on solid again.

I measured the battery voltage at idle, and it's around ~12 volts. It increases to ~13.5 at higher RPM. When I measure the voltage at the generator or regulator at idle, it's around 3 volts, and then suddenly jumps to ~13 volts as the RPM increases (hence the light on at idle but not at higher RPM).

I'm obviously missing something here, but I'm really struggling to know what it is. Ideas?

[midatlanticys]

Is the pulley diameter on the rebuilt gen. a stock size? If it's too big, it might not be rotating/generating fast enough at idle to turn off the dash light.

[jeb1978]

So I did some voltage checks this afternoon...

First, at 1000 RPM with the generator light on:

D+ 1.45 V at the generator, 1.45 V at the regulator
DF 0.7 V at the generator, 0.7 V at the regulator
Terminal 61 at the regulator 2.1 V
B+ at the regulator 11.91 V
Battery voltage at this point 11.91 V

At 2000 RPM with the generator light off:

D+ 14.3 V at the generator, 14.3 V at the regulator
DF 4.8 V at the generator, 4.8 V at the regulator
Terminal 61 at the regulator 13.2 V
B+ at the regulator 13.4 V
Battery voltage at this point 13.4 V

Battery voltage with the engine not running was 12.20 V

I did a no load test of the generator. It had ~1.3 volts at idle, and the voltage increased to ~60 V as the RPM was increased (not sure how high, but likely at least 3000 RPM).

Seems like the generator is working, but the cut-in speed is high for some reason? I checked the pulley diameter on the Bus and compared it to an old scrap generator I have lying around and both were the same at approximately 110 mm.

I also tried for the heck of it:

Used a jumper wire to piggyback on each wire from the generator to the regulator, but just one wire at a time (first D+, then DF, then ground). Light still on at idle. Also did the same for regulator to ground, and then B+ to battery. Light still on at idle. I also unplugged any non-stock items from the fuse box, including my cigarette lighter, radio, and tachometer. Light still on at idle.

[Hippie]

Try cleaning the stack of terminals on the post on the starter where the
12V from the battery + all join up to run forward to feed the dashboard fuse block.

If the voltage to the fuse block is lower than the voltage on wire 61, the
gen lamp will see a partial ground through the ignition circuit, et al., and
illuminate.

[jeb1978]

I cleaned the wires/connectors at the rear of the starter a week or so back. I found that one wire didn't even have a connector on it (the PO had just stripped the wire and wrapped it around the post!). New connector installed, all terminals cleaned.

[Hippie]

Well, there goes my last idea. Shoot.

[jeb1978]

I do have an older Bosch regulator (relay type) in my box of parts. I'm going to assume it's a 30 amp since it came from a Bug that was being parted out (that had no charging issues as far as I know).

So I installed it the other day. Started engine, light was on at idle. I blipped the throttle, the light went out and stayed out. So I went back and took some measurements:

At 800 RPM:

D+ 11.55 V at the generator, 11.60 V at the regulator
DF 0.09 V at the generator, 0.05 V at the regulator
Terminal 61 at the regulator 11.64 V
B+ at the regulator 11.08 V
Battery voltage at this point 11.70 V

I also tried to take the same measurements at 2000 RPM, but started getting weird readings from DF at the generator and all terminals at the regulator. The voltage would go from 11 V to 1 V to negative and back again. I thought it was my voltmeter, so I tried again with a second voltmeter I have, and got the same.

Interestingly enough, I had let the engine run at 2000 RPM while digging out my other voltmeter, and by the time I returned, the generator light was on again. I put the engine back to idle, generator light went out.

I decided to take a test drive at this point since the engine was already hot and I wasn't going to be swapping parts on a hot engine. So:

At first the light was out
Come to first stop, light on at idle
Take off, light out
Second stop, light out
Accelerate to highway speeds, light flickers at about 1 Hz around 2200 to 2600 RPM, but goes out at my 3200 RPM cruise speed
Come to stop, light on at idle, goes out as I blip throttle
Accelerate to highway speeds again, light starts flickering at about 2200 RPM again, but continues to flicker at all engine RPM's above this.
Pull back into my driveway, light is out at idle and as I rev the engine to 3400 RPM, no light
Rev engine several more times, sometimes light comes on at idle, sometimes light flickers at higher RPM, etc.

I went to go for one more test drive, and the whine from the engine becomes much, much louder (sounds like it did when the generator was first installed; you really can't hear anything but the whine). Pull back into my garage, shut engine off, and I can smell what I would describe as an electrical burning smell. No smoke, no dust, no parts flying off, engine starts and runs fine. I ran into the house to grab my camera to record the noise, but when I restart the engine, no noise.

I did a bit more checking after the engine cooled down. I noticed the commutator on the generator shaft wasn't very shiny anymore; it was pretty gray. Looked like dust when I ran my finger across it. I also noticed that there really weren't any gaps in the commutator (not sure what the normally shiny narrow strips are called, but it was basically worn smooth. On the old generator in my pile of parts, the gap between the shiny narrow strips was about 1/16" deep).

I took the belt off and spun the generator by hand, no abnormal noises heard. I took one shim from the inside of the pulley to tighten the belt up a bit since it seemed loose, and then started the engine. Light on at idle, off as RPMs went up. I rev'd the engine several times trying once again to get the light to flicker at high RPMs, and it wouldn't.

I then shut the engine off, and the generator light came on. If I keyed on and/or started the engine, generator light went off. I went back and pulled the negative cable from the battery to keep the battery from draining, and heard the regulator click... so I reinstalled the cable, started the engine, generator light on all the time. So either this regulator was near death anyhow or it just died.

I removed the Bosch relay voltage regulator and put one of the solid state ones back on, so I'm back to light on at idle, off at higher RPMs. What is odd is that it seems as the engine warms up, the RPM it takes to turn the light out gets higher, sometimes as high as 3000 RPM.

At least I can drive it a bit and move it around this way, but it still ain't right. When I stopped by the local NAPA the other day, they mentioned something about being able to test a generator if it's still installed on the car. Maybe I'll take it there just to see what happens.

I'm not entirely sold on trying an alternator kit yet since there's no reason what I have now shouldn't work. The bus had a generator all this time with no issues.

[Hippie]

I think it's normal for the DF terminal voltage reading to jump around with a digital meter since it is being fed rapid pulses of DC from the regulator to maintain B+ output within the correct range.

This has been keeping the battery charged, even with the GEN light acting up?

If so, I still suspect there is something funny with the GEN lamp circuit... that the opposite side of the lamp from wire #61 is grounding out or getting a low battery voltage. Perhaps on the connection between the lamp holder and the instrument panel or the instrument panel to the fuse block.

Do you have a panel mount voltmeter or ammeter you can temporarily install to monitor charging conditions with normal driving?

[jeb1978]

I could probably rig up my voltmeter to watch the voltage while driving.

I did check a few voltages at the dash last night with the engine running. Voltage at the connector from the fuse box to the light bar (one that connects with the GEN lamp) was around 11.7 V at idle, and increased to around 13.5 V as the engine sped up. This leads me to believe the generator is charging the system, just not at idle.

Voltage at the GEN lamp connector pretty much matched what I had seen on the terminal 61 connector in the back... around 1 to 3 V at idle (light on), and the voltage then jumps to 12 to 13 V around 1200 to 1500 RPM and the light goes out. The light appears to be correct.

The generator must be charging the battery somewhat, as I haven't had to charge the battery or jump start the engine in the past few weeks I've been trying to fix this. The starter spins quickly each time.

I'm still back to why the light is on at idle, and why it doesn't appear the regulator is doing its job. The older relay one (before it died) kept the light off at idle, but the newer solid state one doesn't.

I also noticed that after a test drive it seems to take more RPM to keep the light off when the engine is warm/hot (more like 1800 RPM vs 1500 RPM), but that's just a seat-of-pants observation that I can't seem to repeat consistently.

[Hippie]

It wouldn't be the first time I've seen two bad new parts in a row.
See when the light is on, what the voltage is across the gen lamp, the fuse block to ground and the B+ output on the generator itself?

[jeb1978]

I took the battery in this morning to have it load tested, which it passed (no surprises there).

I measured a few voltages afterward.

Fuse block to ground (key out of ignition) 12.10 V

After starting engine, GEN light off (around 1400 RPM):

Fuse block to ground 11.90 V
GEN light to ground 11.3 V
Wire from fuse block to GEN light 13.00 V (I think the engine speed was up a bit at this time due to the choke)

After running for a few minutes, back to idle (800 to 1000 RPM), GEN light on:

Fuse block to ground 11.7 V
GEN light to ground 4.7 V
Wire from fuse block to GEN light 11.7 V

If I rev the engine to where the GEN light goes out, the fuse block voltage goes to around 13.5 V, and the GEN light voltage follows suit.

If I measure voltage from the D+ terminal on the generator (with all wires hooked up), it varies. At idle, I get anywhere from 3 to 5 V, and as I increase speed, it will quickly jump to 12 to 14 V (this is when the GEN light goes off).

Still seems like it's charging at speed, but nada at idle. What I don't have is a feeling to what should be seen on a system with no issues.