Here's an odd one. Bought a 1992 240 for my daughter - it runs great, but every single light on the dashboard was on. (got a sweet deal).

After the battery drained a couple of times - It sunk into my thick skull and I realized the alternator was dead. I replaced the brushes - but to no avail - ended up replacing the alternator with the Autozone classic lifetime warranty model. (note I only found 3 wires - a positive on the D+, an exciter, and the ground attached to the alternator chassey Nothing connected to the B+ and no wires hanging around loose either!! - so that is all I had to hook up to the new alternator)

Now, none of the "idiot" lights come on - one would think everything is perfect. (WRONG!!!).

I checked the voltage coming from the back of the alternator and I'm only getting barely above 12 volts (12.06-12.20 range). When I try to turn on the Air conditioner (a necessity here in TN) - it drops down to 11.20 - that won't do!!!

But even stranger - - When I turn off the car, the Alternator Warning light comes on, and stays on even with the Key out. The only way to turn it off, and stop the battery drain, is to pull the ground wire from the battery. Obviously not a long term fix.

Any ideas??????? - - PLEASE

Thanks
Charles

D+ is the large red wire, B+ is the small red exciter wire, and the last one is ground.
Dan

The small exciter wire - didn't go on B+ - it was a Female connection that slid onto a Male (We always called it a spade) connection (labeled with a W) on the back just a bit above the brushes.

Either way - not sure why I would get a short that allows the interior Alternator Warning light to show up even with the key out. That is my real issue.

Small red to D+ is the "exciter"

Big red B+ goes to Battery + by way of the starter.

Maybe that is the reason why it wasn't working correctly in the first place.

Guess I need to put a ring fitting on the exciter wire (instead of the female spade) so that I can attach it to the D+ post.

Will try that one in the morning - and keep my fingers crossed!!!

Thanks
Charles

Hi Charles,

Your mention of the "W" terminal in another response gives me better vision on this post, so I thought I would try to make things clear with a couple illustrations.

The W terminal is for Diesels to provide a tach signal. Not used in your 92. Connecting the exciter wire there would match your symptom.

The D+ exciter terminal is a stud, but usually fitted with a ring to tab adapter, so you should not have to modify your wiring harness, if you just screw on the male spade terminal adapter.







(So what's the D stand for? Bosch says "dynamo", but I like to think of it as "die", because your car will die after taking you a long way from home if this D+ circuit is not working.)
--
Art Benstein near Baltimore

Mistakes are the portals of discovery. -James Joyce

Thanks all for the help.

Created a Jumper to go from the ring terminal on the alternator to a "spade" male connector. - Attached to the D+ and connected the exciter

And Excited - I am - - 13.56 v at idle.

Thanks All - Especially Art, those pictures were perfect.



Now to those E-code headlights my wife wants me to install. . . .

Do you have a whole vehicle, nice and clean, kept aside "for demonstration purposes only"?

Or do you have more than one?
--
1980 245 Canadian B21A with SU carb but electronic ignition and M46 trans in Brampton, Ont.

Hi Trev,

Those alt pics are from a previous post warning of the magpie syndrome in the pick'n'pull. That alternator was attractive and easy picking up on top of a 740. But it was a pig's ear dressed up like a silk purse by a remanufacturer.

The car was being "zero miled" for one of my daughters.

Last week you learned I have a web site. This week I'll tell you, yes, I have more than one 240. Click on my BB profile.


--
Art Benstein near Baltimore

Always read stuff that will make you look good if you die in the middle of it.

I'm quickly becoming partial to them myself