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david craig
david craig,
Category: Mercury
Satisfied Customers: 1497
Experience:  owner/mechanic at 3D Automotive
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I just replaced my alternator on my 93 mercury grand marquis

Customer Question

I just replaced my alternator on my 93 mercury grand marquis LS. New battery also. My car is losing voltage I've had a brand new 130 amp alternator put on. Battery and alternator shows good but alternator is not keeping 12.5 volts or will not hold charge. What would be the problem?
JA: Have you checked all the fuses? Do you have a wiring diagram?
Customer: I had it checked out professional check it out but if fuses are good what else could cause this or what type of fuse might be out?
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: New battery new alternator big 3 upgrade checked fuses under hood but not under dash.
JA: Anything else you think the mechanic should know?
Customer: They said its something electrical but think its minor.
Submitted: 6 months ago.
Category: Mercury
Expert:  Tim's Auto Repair replied 6 months ago.

Hi, My name is ***** ***** for the delay.

I will do my best to assist you.

do you have a volt meter test gauge? or maybe a multi-meter?

Customer: replied 6 months ago.
Expert:  Tim's Auto Repair replied 6 months ago.

sorry,i missed you last night..

can you tell me the voltage of the battery with the car not running?

also,tell me the voltage of the battery with the car running with no lights,heater ,ac or anything on?

then,tell me the voltage with the car running with everything on,the ilghts,heater ,ac.

thanks

Customer: replied 6 months ago.
With car not running 12.3 volts car running without anything on with about 20 minutes it drops below 11.6 with Ac and lights on it drops below 10.8 until it dies and battery needs recharged.
Expert:  Tim's Auto Repair replied 6 months ago.

ok,,it certainly isnt charging..

do you have ny other electrical problems?

Expert:  Tim's Auto Repair replied 6 months ago.

did you check the 10amp fuse in the fuse box?

Customer: replied 6 months ago.
No.but I will thanks it will be tomorrow until I am able to check since I am out of town right now. Thanks I will let you know.
Expert:  Tim's Auto Repair replied 6 months ago.

ok

check that fuse and also the fuse [30 amp] in the engine compartment fuse box..

if those fuses are good,the problem may be a bad ignition switch,not sending power to the alternator regulator

Expert:  Tim's Auto Repair replied 6 months ago.

PLEASE COPY AND PASTE the link below to your browser, I have uploaded more info on this there please copy and paste the link below to your main browser[INTERNET EXPLORER or FIREFOX]

.

https://www.dropbox.com/s/ethbxq9hybsytvw/0814-grandmarqis-Charging%20System.doc?dl=0

.

if the link doesn’t work that way, try it this way

thanks

.

www.dropbox.com/s/ethbxq9hybsytvw/0814-grandmarqis-Charging%20System.doc?dl=0

.

If you are satisfied with my answer, Please Rate my answer by clicking the rating button so I can get credit for my work. I’m not always going to be giving you good news, so please don't let this stand in the way of you accepting my answer. .it does not cost you more money and we will still be able to communicate, ,.please understand, i can not see, hear or touch the vehicle and only know what you tell me. Bonuses and positive feedback are appreciated.. if you are not satisfied with my answer, please do not leave bad feed back ,i will gladly opt out and let another expert handle the question. .if i have sent any diagrams, please print them. .sometimes you may need to right click the image [,then save picture as]to save it to your computer so you can open it with your picture program...Please ask if you need more help

Customer: replied 6 months ago.
Also another minor problem that also concerned me was that certain times when I would stop at a stop sign or traffic light it would have a weird idle a and the smell of exhaust fumes coming through the a/c. But when ever I would put it in park and idle the car with a couple of firm taps on gas pedal it would stop and run normal.what could be the problem with this sir?
Expert:  Tim's Auto Repair replied 6 months ago.

that be cause by a few things.

it may just need a tune-up.new plugs and plug boots..

the egr valve may be dirty and needs to be removed and cleaned.

or the catalyst converter could be clogged or damaged

thanks

Customer: replied 6 months ago.
Well just had all fuses checked out all were good ignition switch is good also.
Customer: replied 6 months ago.
Still loosing power.
Expert:  Tim's Auto Repair replied 6 months ago.

ok

i will opt out,,perhaps one of the other guys has a better idea of what is going on here,,

someone will be right with you

thanks

Customer: replied 6 months ago.
Ok
Customer: replied 6 months ago.
Thanks
Expert:  david craig replied 6 months ago.

Hi Im David, when the battery is charged up and reading 12.5 volts, start the vehicle and take a reading at the large cable on the alternator. voltage should be 14.4 vdc. let me know

Customer: replied 6 months ago.
No its reading below 12.5 volts when running and continue to drop.
Expert:  david craig replied 6 months ago.

ok, was it a reman alternator or a new one?

Expert:  david craig replied 6 months ago.

i know youve check fuses but here is a print to maybe show you one that was missed.

Customer: replied 6 months ago.
New. No but does one of the silver fuses have anything to do with alternator?
Expert:  david craig replied 6 months ago.

silver? send me a pic please

Customer: replied 6 months ago.
Ok
Expert:  david craig replied 6 months ago.

that sucks. i was hoping if it was leakage i would have been from the lower intake manifold like i mentioned....

Expert:  david craig replied 6 months ago.

sorry wrong customer...

Expert:  david craig replied 6 months ago.

pic coming?

Expert:  david craig replied 6 months ago.

do you still need my assistance?

Expert:  david craig replied 6 months ago.

hello?

Customer: replied 6 months ago.
I took it to a mechanic and he said that it was a short circuit.
Expert:  david craig replied 6 months ago.

a short circuit to the alternator?

Customer: replied 6 months ago.
Module
Expert:  david craig replied 6 months ago.

so it was dragging down the battery and alternator voltage... hmmmm. well glad you got it fixed

Expert:  david craig replied 6 months ago.

you can leave a rating so i can close this one out, thanks and have a nice evening.

Customer: replied 6 months ago.
Yea