Cadillac & LaSalle Club Discussion Forum

Cadillac & LaSalle Club Forums => Technical / Authenticity => Topic started by: fasted55 on August 14, 2012, 02:18:30 PM

Title: generator light stays on - 1979 Coupe DeVille LeCabriolet
Post by: fasted55 on August 14, 2012, 02:18:30 PM
OK.  I used search and I think I know the answer. It has to do with the "generator" light staying on with the key off.  The light works as intended prior to start and goes out with the engine running.
Auto climate control:
                OFF   ECON   LOW    AUTO     HI    BILEVEL  DEFROST
gen light    faint  faint    bright   bright  bright  bright      bright
fan mtr.      on      on       off       off      off       off          off

Which of my climate controls are bad?

Thanks, Ed
Title: Re: generator light stays on - 1979 Coupe DeVille LeCabriolet
Post by: Dave Shepherd on August 14, 2012, 08:10:58 PM
Coul be a bad diode in the alternator.
Title: Re: generator light stays on - 1979 Coupe DeVille LeCabriolet
Post by: fasted55 on August 17, 2012, 05:13:23 PM
Does anyone know if the alternators are one piece (i.e. voltage rectifier built in)  of if you can replace the voltage rectifier independent of the alternator?
Thanks,
Ed
Title: Re: generator light stays on - 1979 Coupe DeVille LeCabriolet
Post by: 76eldo on August 17, 2012, 05:21:34 PM
Ed,

I think I mentioned that you have a bad alternator, as well as someone else.

It's easy to get to and replace, easy to find as a commonly available part.  It has an internal regulator.
They symptom exhibited indicates a bad diode, allowing current to pass to ground, hence the light, and battery drain.

Should be about 225.00 done by a mechanic or $125.00 done by you.

Good Luck,

Brian

PS... I'll buy your car in a heartbeat if you get fed up with your electrical problems.
Title: Re: generator light stays on - 1979 Coupe DeVille LeCabriolet
Post by: fasted55 on August 20, 2012, 11:03:20 AM
Hi Brian,
OK, I'll accept the alternator as having a bad diode because as you point out it's a relatively inexpensive fix.  And "my" mechanic thinks so as well, saying it's hot around the negative terminal.  There may still be something with the auto climate controls but first things first.  Before wanting to buy the car, you should know that I got taken.  By that I mean the seller did a quickie spray job on engine and engine compartment, at least things that showed in the photos.  Anyway after putting the car on the lift and having it gone over I'm dropping over $4K to make it driveable.  All new fluids, gaskets, hoses, belts, filters, shocks, some suspension pieces, etc.  Admittedly, much of that is labor but still.... If I ever buy another car sight unseen I should be shot. 
Regards,
Ed
Title: Re: generator light stays on - 1979 Coupe DeVille LeCabriolet
Post by: 76eldo on August 20, 2012, 12:54:53 PM
Ed,

No one should buy a car sight unseen unless you are comfortable that the seller is representing the car 100% honestly.

I have sold cars on ebay but provided full disclosure and encouraged bidders to have the car looked by someone in a club or an inspection service.

I also inspect cars and handle complete transactions for foreign buyers.  In the past I have negotiated deals on some expensive Classics and muscle cars, handled all finances, and delivered cars to the port for export.

It's too bad you got "taken" but, in my opinion, these H & E Le Cabriolet's are worth sorting out and getting right.  Especially a 79, which mechanically was one of the best years for Cadillac.

Good luck,

Brian
Title: Re: generator light stays on - 1979 Coupe DeVille LeCabriolet
Post by: Dave Shepherd on August 20, 2012, 07:40:56 PM
I say again and again, look at these cars first, as mentioned by 76Eldo. I do appraisals around upstate area of N.E. and most are misrepresented out of ignorance on the sellers part rather than fraud.  Forget the pics and claims, receipts and documents are required to prove recent repairs.