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Electric pump or motor stuck on?


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My -90 Eldorado has been left alone for a while. Battery unhooked. Started up a few days ago. Now, when turned of I can hear a tiny noice as from a very small pump or electric motor. Seems to stay on permanent. Buzz comes from the right side of engine bay I think.... No obvius sorce on top of engine.

Help!

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The right side of the engine bay from the perspective of being seated in the car?

@Göran W

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Does that have a vacuum pump? I wouldn't think so

A few things come to mind.

A relay

Horn

Is the suspension pump located in the front? 

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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From the driver seat, yes  No other way to determin left or right on a car! But I can not hear the sound from there…..

Relay? Doubt that. The sound is to "soft" and even.

Horn? No. Same reason.

Suspension pump? I Think it sits in the rear.

Vacuum pump? Maybe. I can feel it on some vacuum lines but I can not find the pump??? Why does it stay on?

 

Edited by Göran W
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The vacuum pump may not have been on the 1990. The 1988 or 1989 with the 4.1 may have been the last year for the pump.

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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9 hours ago, Göran W said:

From the driver seat, yes  No other way to determin left or right on a car! But I can not hear the sound from there…..

Relay? Doubt that. The sound is to "soft" and even.

Horn? No. Same reason.

Suspension pump? I Think it sits in the rear.

Vacuum pump? Maybe. I can feel it on some vacuum lines but I can not find the pump??? Why does it stay on?

 

Hi @Göran W. Not trying to be insulting by asking left right perspective.  I knew nothing on the right that could cause a noise like that, so I wanted to be sure we were on the same page.   That said, I had a 91 4.9 so I dont have direct experience with the 4.1/4.5.  

Here is a fun fact, in the following link is a post by "The Guru" from 2005 on vacuum pumps, his screen name is chevelle.  See this discussion for more:

https://www.cadillacforums.com/threads/ht4100-vacuum-pump.55454/

 

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I posted a link to the 4.1 solely due to the mention of the vacuum pump, if for nothing else for information purposes and The Guru's post.  

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Take a 3/4 inch hose and use it as a listening device.  Listen to the alternator.

Is the battery retaining its charge?

See this thread

https://r.tapatalk.com/shareLink/topic?url=https://www.jalopyjournal.com/forum/threads/alternator-works-great-but-hums-when-ignition-is-off.853425/&share_tid=853425&share_fid=11843&share_type=t

 

 

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Check your HVAC fan.  Some GM models the fan runs all the time.

Esp. the a/c equipped cars!

A ancestor of GMs old "flow thru ventilation"

Pull the fuse for your HVAC and see if noise stops!

My Z-28s fan HVAC fan runs all the time and sounds like a hum/clicking when you turn the key on.

Very slight noise BTW!

 

 

Edited by sonjaab

93 DeVille-13 Chevy Impala

72 GTO - 77 Triumph Bonneville

84 Z-28

Syracuse NY

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It´s for sure the alternator. Guess it has been replaced with the wrong substitute. Can anyone confirm the partnumber and what it will take to fix? From what I´ve learned two of the four lines should change places? The alternator must come out since you can not even see the connector under there.

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  • 2 weeks later...

Finally got to removing the alternator. The humming sound ended when disconnecting the multicontact. Check with voltmeter in contact gave as follow:

P = Not used

L = 4,6 mV

F = 1,5 mV

S = ~ around 100mV

Ignition off, battery connected.

I initially belived that someone had mounted the wrong alternator but I don´t know enuff about the alternator to understand what´s wrong. Please help.

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Heres the recommended NEW 120 amp alternator. 

GM part #s   

 

10463121, 10463122, 10463545, 10463546, 1101490, 1101519, 7942

$102.xx US 

https://www.rockauto.com/en/moreinfo.php?pk=3468264&cc=1026177&jsn=420

Edited by sonjaab

93 DeVille-13 Chevy Impala

72 GTO - 77 Triumph Bonneville

84 Z-28

Syracuse NY

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The gaskets are gonna be a tough find.

Try www.top-downsolutions.com  or send the owner Lon a PM.

He might know.

Glove box lock hmmmm....gonna have to do a e-bay search or your local parts yard.

But prob. not too many Caddys in the parts yards where your at.

 

93 DeVille-13 Chevy Impala

72 GTO - 77 Triumph Bonneville

84 Z-28

Syracuse NY

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  • 4 weeks later...

New alternator in. Noice gone!😎 But… One down and new one shows its uggly face.😕

Tested the windows. Driver side worked just fine, passenger side came down about 2 inch and then… WHAM!!! It fell all the way to the bottom. Wtf happened?

Guess I´ll have to open up the door all the way but don´t know what to expect????

 

BTW, I´ve got "service code 37" and "restraint 37" in DIC. Can not find this in the service manual. Anyone?

 

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