Generator light doesn't come on with ignition

jamlip · 08-10-2016, 04:39 AM

Hi all,

I'm just finishing-up restoring a '68 912 and have noticed a peculiar issue.

The generator warning light does not come on when the ignition is turned on. I understand that it is supposed to go on with the first stage of the ignition, and then go out when the engine is running.

I am using a Bosch solid state reg, and the wire is attached to post 61. I have tried a second regulator with the same results. I have checked the warning light is working - it illuminates when 12v is applied across it.

Other than this, the charging system seems to be working fine.

Any ideas greatly appreciated.

James

Jaems · 08-10-2016, 08:14 AM

The wire may be broken. Apply 12v to the wire at the regulator and see if the light comes on. If it doesn't then the wire is broke. The wire should be blue in color.

jamlip · 08-10-2016, 01:44 PM

I have checked the warning light is working - it illuminates when 12v is applied across it. This is 12v from the terminal connector that attached to post 61 on the regulator.

Jaems · 08-11-2016, 09:30 AM

There are only two wires leaving the Regulator. One goes to the battery (black) from 30 B+ and one goes to the red generator light in the combination instrument cluster(blue).

If the there is 12v power at post 61 at the regulator and there is not 12V to the generator light in the combination instrument cluster. Then you have a break in the blue wire somewhere between post 61 and the light in the CIC.

Or
If non of the other lights hand break and oil pressure light work. Then there is a break in the blue/yellow wire. or the brown ground wire needs cleaning. These are the only wires that will effect the generator light in the dash.

Or get a wiring diagram or take it to a Porsche mechanic.

Jaems · 08-11-2016, 09:43 AM

Since you live in the UK. There is a gentleman name Mark from Hampshire, United Kingdom. Uses the handle 912UK on the the 912 BBS. He is very knowledgeable about the 912. He should be able to help you.

ganun · ganun's Garage

Very nice Staggerwing and J3, not so sure about the 912 though. oops not a J3.... gas tank in the wing?

01:42 PM

James,

Please check your ground terminals. A solid state version of the regulator might even be more sensitive to a poor grounding. And ... are you sure to have the correct replacement Bosch regulator?

I forgot something important: The charging light (the load of the lamp) is part of the functionality of the mechanical regulator. Please check if the solid state replacement also uses the lamp as part of the charging system. A different - or just the wrong - control light lamp could be the cause of your problem. So check if the solid state regulator is a 1:1 replacement, including the same control light.

Otto

jamlip · 10-23-2016, 03:45 AM

Update on this issue - turns out my generator was shot. It did seem to work, but there was obviously something wrong with it because it eventually overheated, spat solder everywhere, and wouldn't output at all.

So I replaced it with an alternator conversion kit.

10-23-2016, 04:01 AM

James,

Thanks for the feedback. Good to know that your problem has been solved and you are able to drive your beauty again!

Otto