TheSamba.com :: View topic - Gen Light stayed on after shut-off?

Tue Nov 10, 2015 7:23 pm

So I got home from work a few minutes ago, just finished dinner actually.
But when I shut the engine off my generator light came on? Which isn't unusual for it to flash as the engine is dying and the key is still "on" but it's still on and I don't know why?
Any ideas?

Tue Nov 10, 2015 7:28 pm

smack the volt reg with screwdriver handle- if it stays on check at the coil see if you have a keyswitch problem or shorted wires. disconnect and reconnect the battery if it stays off- possible vr.

Tue Nov 10, 2015 7:31 pm

Alright I'll check all that tomorrow, this dang daylight savings means it's already midnight outside....
Another oddity I forgot to mention is that the light turns OFF when I turn the key on (not starting the engine just power on) which is obviously backwards since it should be on with the key on before I start the engine...

Tue Nov 10, 2015 7:33 pm

sounds like sticky points in the voltage reg then.

Tue Nov 10, 2015 7:38 pm

Possibly, it's a new, and probably cheap Chinese VR. Thanks for the tips.
I'll update everyone tomorrow with my findings.

Tue Nov 10, 2015 8:05 pm

The points in the regulator are stuck and it's trying to make the generator run like a motor. Undo the battery cable or you'll have a dead one.

Tue Nov 10, 2015 8:16 pm

Another interesting update after going out to disconnect the battery as per Donnie's advice.
After moving a bunch of stuff around in the back to lift the seat back up to get to the battery I noticed that the light was off now. I was worried it had already somehow killed the battery so I put the key in and turned it on and guess what! The oil and generator lights both came on.
I still unplugged the battery to be safe but seems kinda odd.

Wed Nov 11, 2015 9:11 am

Don't worry, I'm sure it'll happen again.

Wed Nov 11, 2015 3:44 pm

that happened to me once, I remembered that it happened very shortly after I had lifted the backseat and then put it back down. What I noticed when I picked the seat back up, the seat belt buckle was shorting out the voltage regulator. It just fell when I lifted the seat and I was in a hurry and didn't realize it fell against the voltage reg. Hope that helps

Richie

Thu Nov 12, 2015 11:50 am

I've had that happen to me too. Turned out both the brushes were worn out (beyond their limit), and the VR took a crap. Seemed I was on borrowed time with them (VR and the brushes). This was at 2AM after getting back home (had been using the headlights for over 4 hours). The weird thing was the VR never gave any indication that it was dieing. Usually they chatter right before they quit (had that happen too).
Replaced the brushes and VR and I've been good to go now for over 5 years now (knock on wood). :wink:

Thu Nov 12, 2015 11:52 am

Well so far it hasn't happened again, I do have two more VRs floating around in the cargo area (although one may be bad) just in case as well as most of my tools. I'll see if it happens tonight (when I have the headlights on for the whole hour drive.)

Tue Apr 04, 2017 6:54 am

Sorry to resurrect an old thread but this same thing happened to me today. Lately I'd been having occasional problems with the Gen light staying on after the car started, but a tap on one of the brushes always corrected that. Now though I think that brush is fully worn as the little circular spring that applied pressure to it seems to be resting on the steel guides for the brush. I was anticipating this and ordered some spare brushes, so I'll replace them at lunch time. Any advice or lessons learned for parking lot generator servicing would be appreciated.

While tinkering with the brush at work I turned off the car and this was the first time I saw the Gen light come on after the engine stopped. I tinkered a bit more and got it to go off...so at least I'm not draining the battery. Hopefully the VR isn't dead, too, but if so I think I have a spare in the car as well, and that's a pretty easy fix.

Advice welcome...thanks!

- Doug :-)
'73 Fastback, stock FI & charging system

Tue Apr 04, 2017 8:14 am

Take the battery ground cable loose.

When you do the brushes, loosen the generator strap so you can turn the generator to get to the bottom brush. Be very careful with those screws so they don't drop down into the tin somewhere. Also watch the brush springs so they don't jump off and go flying somewhere.

I like to put some sandpaper (not emery cloth) on the end of a wooden stick and, with the engine running, put it in the top brush holder while the brush is out. This brightens up the commutator. If you're so inclined you can take something like a mechanic's pick and clean the slots in the commutator while you're at it.

Tue Apr 04, 2017 10:33 am

I didn't end up having any sandpaper with me, but I did replace the brushes and all seems to be well now. I get the light on when I initially turn the key to the On position, then it goes out with the engine running, and finally goes off when I turn off the key. I'll definitely do the sandpaper thing when I have a chance, though...just nice to know I can drive with my headlights on (helps keep the MD drivers from ramming you) this evening without the engine quitting on me.

- Doug :-)

Tue Apr 04, 2017 10:55 am

Tell me about it. I moved one wire so that my parking lights and taillights come on any time the key is on, so I have daytime running lights. These days people are so used to seeing them, that if you don't have any, they don't even see you. I had several near-misses until I did that.

Tue Apr 04, 2017 10:59 am

Interesting, too, that we both have green cars (though mine is L61B Sumatra Green). I really thing there's something about green that people don't see. I paid $300 for the car in '97, and since then have made $4000 from people hitting the car on 2 separate occasions. I just keep welding it back together and keeping the paint up. It's straight and solid, but with a passenger side A-pillar hit and a driver's side B-pillar hit the doors don't quite seal anymore :-/

- Doug

Tue Apr 04, 2017 11:56 am

Usually when the generator light comes on after you turn the key off, it indicates a problem with the voltage regulator - specifically that the cut-out points are sticking closed.

Normally those points are supposed to open when there is a back-current flowing from battery to generator over a couple amps - this electrically disconnects the generator from the battery.

If the points stick closed then current can flow from battery to generator - this means the battery is trying to spin the generator like a motor except it can't because of the belt & engine being turned off. This will drain the battery pretty quick.

This assumes of course you have the original style electro-mechanical regulator and not a solid state version.

Tue Apr 04, 2017 12:06 pm

Yeah, it's still the original VR, and the replacement I have in the car is the same type, just new. I bought it in 2006 when the car was first t-boned and never needed it. Guess it's a good thing I keep it in the car, just in case this is the beginning of the end for the VR.

Thanks again for all the suggestions here! TheSamba and its awesome members come through yet again :-)

- Doug :-)