My GEN light is always on when my car is running. Any idea's why?

Thanks

 

Check your fuse, small sheet metal grounds under hood and firstly running voltage to see if the alternator is putting out voltage above battery voltage.

 

The alternator is brand new, it's a 220, is that possible it's to much? All fuses are fine, I checked those 2 days ago, the battery is pretty old, but has been kept in a trickler the last 2 months.

 

Also, have new belts, none of them seem to be slipping, as far as i can tell

 

mine is also on. i was told to try replacing the voltage regulator. but i noticed there is also some sort of regulator on the driver side in the engine area that the alt. is wired into & im wondering if that might be the issue.....

 

I assume you now have an internal regulator?? The original alternator may have only been a 37 amp.... The diode trio is a common cause of a gen light while engine is running.

 

Back up.

Is this a stock external regulator system, or has the car been converted to internal regulator? Was the light functioning properly BEFORE the new alternator?

 

stock external regulator system.

When I first purchased the car this past summer, it had the GEN light on also, with a 260ci motor. I replaced motor, alternator, HEI and re-did some wiring under the hood, and the GEN light is still on.

There is some pretty sketchy wiring under the dash from the previous owner, I did some digging around the other day but didn't solve anything.

 

Can you post picture of your alternator. I do not thing a 220 Amp one is compatable with an external/stock regulator.

 

Is the light on when the key is in the RUN position but the engine is not running?

 

I'm almost positive it is, I'm currently at work, but will get a picture tonight.

I don't believe it is. Only the "COLD" light is on

 

The GEN light is SUPPOSED to be lit if the key is in RUN and the engine is stopped. This tells me that either there's a problem with the wiring in the dash.

The way the GEN light circuit works is that one side of the bulb is fed from a +12v source that's on with the key in RUN. The other side of the bulb is connected to the field wire in the regulator. This wire is grounded when alternator output is too low (or zero) and is at +12v when the alternator is charging. It's possible that the problem is in the regulator also.

By the way, I've never seen a 220A, externally regulated Delco alternator for car use. 37A, 55A, and 63A are the most common.

 

Thanks Joe, and everybody else, I will play with it this weekend.

Joe I found one of your old post here with great advice, I will do this method and hopefully it will at least tell me if it's wired correctly.

 

Just wanted to follow up, I got the car out today, and the GEN light is on when the key is turned on (car not running) and when the car is running. So it's always on.

I snapped a pic, I looks like There is a "Rig" wiring job going on underneath the hood.

DSC03610.jpg

DSC03611.jpg

 

The alternator appears to be the internal regulator type. I dont know if the wiring is correct for this as it appears that the external regulator is partially in use.... I dont know what your solution is but if it were me I would get an original type alternator and put the wiring back as stock.

 

The wiring was all done by the shop after the new motor swap. The GEN light was one with the old 260ci in also, but I kept the same external regulator, maybe that is bad? Or maybe the wrong alternator was also used on the 260ci

 

220 amp proberly take 30 hp to turn it and 3 belts.

 

Find a new shop!

Yes, that's an internally-regulated alternator. You should not be using the old external regulator. You also should NOT be using wire nuts for automotive wiring! Here's how it should be wired:



Note that the external regulator is eliminated. The brown wire is connected to the blue and the red to the white in the four-wire connector.

 

way to go Joe Get a new shop

 

discussed my concern with the shop today, they stated that this previous wiring was already there, must of been from the previous owner.

When I picked the car up it was a wiring nightmare...

Here is a pic of the first day I got it

motoreg.jpg

I need to have somebody re-do all the wiring i think, I know it's way over my head

 

Joe gave you the correct diagram.
Go print it, sit down and look at the wire COLORS in the engine bay for the alternator to
the external regulator . It will click in your head. This is how I got started on learning my
wiring system. This is pretty simple even for a newbie.

5 simple rules to follow. Cut, strip, crimp, solder, heat shrink. No wire nuts.

Shortly thereafter i completely wired my 78z with an American Autowire highway 22 harness.
Now if you really want to have some fun , that is VERY VERY newbie friendly.
There's NOTHING worse then having a fubar'd electrical system. Trust me, been there for years.
Risks of breaking down anytime , anywhere make your car a liability to you.

The schematics are idiot proof. Painless is too complicated for a newbie to understand.
If you need help I can show you what you'll be dealing with if you want to try it.
There's high quality OEM harnesses that are simply plug and play.
http://www.americanautowire.com/factoryfit.html

If you can understand this sub-schematic which is 1 of 6, you can do it.
1 simple rule. Everything has a power wire, and a ground wire. That's how simple it is.
http://i46.photobucket.com/albums/f1...Schematic2.jpg

 

Thanks for the confidence boost, I printed off your diagram and Joe's And I will attempt to fix the situation. I'll pick up a 4 way wire connector and some heat shrink wrap as well.

 

FYI !!!!

Joes diagram is the one you need, NOT the one I posted.
The one I posted was just to show you how easy it is to read the American Autowire schematics.
It's NOT for your application.

Can you post the plug of the alternator ??
I'm curious if they gave you a 12SI alternator or CS130 if it's 220amps.
The charging wire back to your battery (big fat red one) should be 4 gauge minimum
Can't use the stock wire when you're generating nearly 4x the juice through it.

I hope they didn't FUBAR your alternator you paid good money for because of their retarded install.
I'm assuming you plan on putting a couple stereo amplifiers in this car for the big alternator ??
.....and maybe an electric fan ??

I just ordered a 220amp for my brothers 2000 GMC Jimmy this week myself for that reason.

 

Alright, Per Joe's diagram And going by my old external regulator

DSC03611.jpg



The #1 wire from my alternator is white, and #2 is red. Looks like from the diagram the wires should be blue/white

Since my wires are different colors, I'm guessing I connect #4 on the regulator (brown wire) to #1 on the alternator (white wire) and Connect #3 on the regulator (red wire) to the #2 (red wire) coming from the alternator

 

I will get a picture for you, I believe it's a 6 guage wire.

Also I don't plan on running any amps, Just install a CD player in the glove box a single 6x9 in the rear seat (i believe thats the default size) and a new dash speaker.

 

Okay, something isn't right.

You said you have a 220 alternator. Did you mean 220amp or is that a model # ? If it's a 220 amp,
they're NOT cheap, so you'd know. Most people use beefier generators for adding on electrical drain
devices like amps, electric fans, fuel injection, etc.

Do you have the info on the alternator you bought and from whom it was bought ??

Side note about the external regulator wiring.
Looks like the white wire was cut, and mated to the blue wire with a wire nut.
Then at the bottom of the regulator the OTHER end of the blue wire is mated to some unknown wire going behind the regulator.
IIRC the brown wire is the voltage sensing wire to excite the alternator's charging.
But don't quote me on that.

 

I'm pretty sure you'd be hard pressed to find a 220A version of a 12SI alternaton, even aftermarket.

The only wiring you need to worry about with this alternator is the red wire in the harness needs to connect to terminal #2 on the alternator. The brown wire in the harness needs to connect to terminal #1. The large red wire from the threaded BATT stud on the alternator goes to the junction block on the horn relay.

By the way, the wires coming from your voltage regulator ARE the same colors as the diagram. Clean the crud off of them with lacquer thinner. The white wire has yellowed. Also, it looks like the wire nuts do connect the wires as shown in the diagram, however the fact that they are still connected to the voltage regulator may be causing a problem. Unplug the connector from the voltage regulator and see what happens. Of course, I don't trust the wire nuts. I'd actually remove the wire nuts, solder the wires, and use shrink tubing.

 

I apologize, I just looked at my receipt for parts I purchased and it's a 120amp 12 volt 1 wire

http://www.summitracing.com/parts/PRO-66445-12N/

 

Well that makes more sense then.

http://www.madelectrical.com/electri...hreewire.shtml

Check the table and see what you're not getting with a 1 wire alternator/generator.
IIRC the downside of 1 wire alternators is they only charge above 1500rpm.
So at idle, you're not charging.

3 wires are better.

 

For future reference, it would have helped to know this right from the beginning. A "one wire" alternator by definition doesn't have the field wire necessary to properly control the GEN light. Either change the alternator (the preferred approach) or remove the bulb. For the life of me, I can't understand the attraction of the "one wire" alternators. What's really ludicrous is that first the aftermarket has brainwashed everyone into thinking they must have a "one wire" alternator, THEN the aftermarket starts selling a $25 electronic module to essentially replace the GEN light function that comes for free with a normal three wire unit!

 

When building my 425, I really didn't have much knowledge, and asked a lot of help on the forums. A 1 wire was recommended, so obviously I went with it. I would like to do it right, so I will replace it with the correct alternator instead of removing the bulb.

What amp do you recommend for a 12Si? A 105, 140 or 170? I don't plan on running any amps for speakers, Only thing I may add is an electronic fan down the road if I run into heating issues.

Or could I use a 10Si?

When I get the correct alternator, then I follow the wiring diagram you posted correct, Joe?

Thanks for your patients with a newbie guys

 

Your stock alternator would have been 37A (55A with A/C). Unless you have some very large non-factory current draw (and it sounds like you don't), there's really no reason to pay for the large custom alternator or to put up with the HP loss from it. Even a stock 78A 12SI from a 1980s B-body will be more than enough for your application.