[nothingbutford]

Hi, This is my first time posting on this board, but I've been here a few times before just to look around.

My brother has a 1999 Taurus SE, Vulcan engine, 75000 miles, original alternator, outdated(NAPA) battery. The problem is this: Since a few weeks ago he will be driving along and all of a sudden his headlights will dim, all electrical dash instrument stop working, and battery light either comes on or flickers. If he slows down or stops it would pick itself back up and he could drive again.

Today he was going to church and it did it again, only this time the engine shut off and wouldn't even turn over. After about twenty minutes when we got back to the car he tried it and it started right up! Tonight on the way back from church it stalled again, this time I was with him. The engine started running rough, lost all power, jerked a few times, and then died and wouldn't start back. We were able to swap batteries from another vehicle and it made it home fine, but the battery light is still on.

I'm thinking that his alternator went bad and ruined his battery thus meaning he needs a new battery AND alternator. What I can't figure out is why the engine acted like it did with all the sputtering and jerking. I guess if the spark plugs couldn't draw enough power it would do this? Could a bad alternator cause a malfunction in the PCM? He is taking it to Advance Auto to get the alternator tested tomorrow and then we'll hopefully find out something. What do you think?

One other thing is his windshield wipers switch on and off frequently. We've been told it is a bad wire/connection in the steering column somewhere?

Any help is greatly appreciated.

 

[Racer X]

A low voltage condition would cause erratic drivability.

Before you assume anything else, have you tried cleaning the battery contacts with a battery terminal cleaner?
Be sure to clean the posts as well as the terminals.

 

[shoz123]

The cars have a battery saver relay in them. When the battery voltage drops below 11V it will start turning things off. Indeed for what ever reason it seems the battery is/was dead.

The wipers is the Multi Function Switch that needs cleaned out or replaced. This is in the turn signal stalk.

 

[jdaniels]

Ground strap.....

 

[nothingbutford]

Thanks for your replies.
I haven't cleaned the terminals but there is no corrosion at all and they look very clean.
What would cause the voltage to drop below 11V? Alternator?
Is the multifunction switch something I can fix? Any diagrams available anywhere or such?

Thanks a lot for your help!

 

[shoz123]

For the voltage to drop it would be the alternator not doing it's job. When the car is running check the battery voltage it should be above 13.5 V.

The multi'function problem is easy. Just pop the end off of the stalk and clean it out. There will be a bunch of grease n there.

 

[mrclean]

A few posts back or possibly in the archive, there is a guy that has detailed pics of pulling off the cap on the multifunction switch, so try looking there to give yourself a better idea.

 

[nothingbutford]

Advance replaced the alternator and THAT is fixed now. Tonight when he picked it up he said that when on cruise control the tranny shifted in and out. I think it was probably the TC lockup going on and off? And he said when he turned the cruise off it didn't coast normally - it was like the TC was still locked up and the engine was braking him. He also said it shifts around 4000 now instead of 5000 like he had it trained. Is this a PCM problem or just it relearning his driving habits?

Thanks for the info on the switch. I'll look that post up and check it out.