Help With Lights Dimming and Instarmental Panel

[AvalonJohn]

It all stated about two weeks ago when I noticed my RPMs going up and down a little and Instament panel lights dimminging and then going back to normal when stopped at a light. Also the car would surge a little when at a stop. That has been happing on and off for last two weeks. In addition, last night while driving the the headlights strated to dimm and then go back to normal as well. Does this sound like the alternator or voltage regulator? I have a 1999 LX 3.8 liter.

ThaNKS,
AvalonJohn

[wiswind]

There can be a few causes of this.
I will start with cheap/easy.... as I like those solutions.
I had a vehicle once that did this....even would completly die (interior lights go out and starter not turn over when I turned the key to the START position).
The cause....corroded battery terminal to battery cable connection.....they looked perfect......were tight......yet that was where the voltage drop was.
I removed the cables one at a time and cleaned the terminals and cable connection surfaces....and re-installed...... and the problem was solved.

Other things could be other connections with this problem...including the big ones down by the starter......and over on the alternator.

Also a slipping belt can cause this...although one would expect that you would hear this.

Then there are the ones that cost some money.....but not a huge amount....that would be a weak alternator assembly (voltage regulator and rectifier assembly are a part of the alternator assembly).
Along with this is the battery......from 5 years old on.....you are on borrowed time.
Younger batteries can fail also.
A failing battery can place a increased load on the alternator.....even causing it to fail also.

[AvalonJohn]

Wiswind-

Thanks for your response. Battery cables are clean. Did them about 3 weeks ago just because they needed it. I will follow your recommendations but think it is likely the battery since its about 5-7 years old. I've got 142 K on the car and replaced alternator with a new Bosch at about 80K along with belt.

Thanks,

AvalonJohn

[tomj76]

>Battery cables are clean. Did them about 3 weeks ago just because they needed it.

I've seen this type of behavior when the battery connections where not tight. Since you just recently serviced the battery cables, it's possible that the connections are as tight as they should be. This would especially be true if the symptoms only began to occur after the service was performed.

[AvalonJohn]

Tom:

Good point and yes I noticed after servicing the battery. Seemed tight when I re-connected but will double check and go from there.

Thanks,

AJ

[AvalonJohn]

Ok guys:

Beginning to suspect a bad Voltage Regulator ? Went to Autozone and they tested and said battery was bad alternator was ok, so I replaced the battery w/ a DieHard Gold. Was ok for about a week, now lights on instramentational panel and headlights are dimming then going back to normal again, frequently ? Also, rpms are going up and down a little when car lights and instramentational panel dimms ? Furthermore, the rpms and speedometer are going crazy somethings when I'm just driving. The speedometer gets pinned at max for a minutes or so and RPMs may go to 50,000 when going 20 mph and engine isn't really turn that high.

Have a 99 windstar w/ 3.8 liter engine. I replaced alternator 3 yrs ago (guessing 70K + since) with new Bosch. QUESTION: Is the voltage regulator in the alternator or can it be replaced w/o replacing alternator ? I've seen where it's stated that it's in the alternator and can't be replaced unless replace the alternator, but looks like they sell just the Voltage regulator by themselves for 99s on-line. Can I only replace the VR and is it easy ?

Thanks,

AJ

[12Ounce]

Relays, relays, relays ....

[AvalonJohn]

Any ideas which ones ? don't know much about them ?

Thanks,
AJ

[12Ounce]

I would buy at least one of the two sizes found in the fuse box near the battery. Mark the new ones someway ... and then go a swap-out trial of any likely candidate. Look in the glovebox manual for a layout.

Start with the "PCM supply" relay, then the fuel relay, next any of the SSP's ... and go thru all with a one-by-one trial and error test.

[tomj76]

It might be useful to monitor the voltage at the battery terminals, especially if you have a meter that will show any short term fluctuations. I'd check it in a few other places too, such as the alternator (generator). Check your ground voltage too (measure the voltage between battery negative and the engine block). It should be zero and even a few tenth's of a volt would be an indication of a problem.

This could also be an engine problem, such as a bad IAC or TPS. Do you have any situations where you feel a misfire or rough running engine other than idle?

[AvalonJohn]

Thanks Guys!! Will give it a shot. Let you know what I get.

Thanks,

AJ

[AvalonJohn]

Anyone know where is can find a site that will give me the parts numbers on the relays in the Power Distribution Box and where I can buy them ?

Thanks,

AJ