This will take you to the main site where there is history, technical information and other information on these cars.
This takes you back to the main page of the forums.
This is the control panel to change your password, information and preferences on this message board.
Click here if your lost your password or need to register on this message board. You must be a registered user to post. Registration is free.
Search this board for information you need.
Click here to buy cool Squarebirds mechandise.
Click here to support For $20 annually receive 20mBytes webspace, a Squarebirds e-mail address and member's icon on the message board.
Prev Previous Post   Next Post Next
Old 07-05-2017, 09:03 PM
simplyconnected's Avatar
simplyconnected simplyconnected is offline
Slow Typist
Join Date: May 26 2009
Posts: 7,520
simplyconnected is on a distinguished road

Michael, I agree with most of what you say IF you qualify your statements.

For example, with regards to GENERATOR circuits... The GEN light is certainly convenient but it isn't necessary. Many trucks and tractors have NO GEN light. Cars only have them as a convenience, not an essential component for the charging system. I personally LOVE having the GEN light for the reasons you raise.

Ok, let's stick with T-birds because they do have a GEN light. In normal operation;
When you first turn the key, the GEN light shines,
When your engine starts, the GEN light goes out,
When you throw a belt, the GEN light shines.

I would expect these conditions to be true in normal operation, all the time, regardless of whether your car has a generator OR an alternator.

Now, we install a self-regulated solid state alternator, commonly found in most production cars. They require a "sense" wire that turns on with the key switch.

Since the original GEN light is fed from the key switch, it serves as a perfect "sense" wire for an alternator. Generators never require a 'sense' wire. Can an alternator system do without the GEN light? No light is necessary, but the alt still requires a 'sense' signal that turns on with the key. Without that signal, the alt won't charge.

But what happens IF the bulb burns out? There goes the signal to the alt. Not only will the bulb stop working but the alt stops as well. This is bad but it only applies to alternators, NOT GEN's.

A simple small resistor will remedy this potential alternator problem. A good bulb will still work exactly the way you would expect (as outlined above). In addition, if the bulb burns out, the resistor still passes enough current for the alt to 'sense' the key is on. Let me say this another way: The resistor never takes the place of your GEN light but it is a safeguard in case the filament burns open. Again, just in alternator systems.

Another small advantage of the resistor is, it passes just enough power to stop nuisance flickering at idle speeds. The diagram below shows the GEN light connected to the 'I' terminal of the VOLTAGE REGULATOR. It turns the voltage regulator on, which in turn turns on the internal solid state components. Otherwise, if on all the time, the battery would drain.

Just a note about ONE-WIRE alternators... They were never used in production cars. Since they don't have a 'sense' wire, they automatically shut themselves off below ~1,000 rpm. This makes 'remote start' impossible to use because remote start stops cranking your engine when the alt starts putting out 'charging voltage'. One-wire alt's need a 'gas pedal goose' upon startup just to begin charging. - Dave
My latest project:
CLICK HERE to see my custom hydraulic roller 390 FE build.

"We've got to pause and ask ourselves: How much clean air do we need?"
--Lee Iacocca
Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 02:01 AM.

Driving, racing or working on cars can be hazardous. The procedures and advice on this website including the message board are opinion only. and its webmasters and contributors do not guarantee the correctness of the advice and procedures. The and its webmasters assume no liability for any damage, fines, punishment, injury or death resulting from following these procedures or advice. If you do not have the skills or tools to repair your car, please consult a professional. By using this site you agree to hold harmless the, its authors and its webmasters from any resulting claim and costs that may occur from using the information found on this site.

Powered by vBulletin® Version 3.6.8
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Any submissions to this site and any post on this site becomes property of . The webmasters reserve the right to edit and modify any submissions to this site. All material on this is site is copyrighted by the Reproduction by any means other than for personal use is strictly prohibited. Permission to use material on this site can be obtained by contacting the webmasters. Copyright 2002-2016 by