Lights flickering

[rtbrjason]

Has anyone else experienced lights flickering? It's mainly noticeable with the interior lights when it's dark out and you open the door, but it's also noticeable in the headlights or radio/climate control display. This problem seems to go away completely when turning headlights off. Turning everything else off like HVAC but leaving head lights on doesn't seem to make the issue go away. I've recently put a new alternator in as well as a new battery. I've also tried running a couple new ground wire from the battery to the body and engine.

It's not a huge deal but is kind of annoying and would like to solve it if possible.

 

[IMINYOURCHAIR]

check that the two connectors going to the alt are not corroded. (not the bigger red one, it should be fine) and if that checks out go from there.

 

[stamp11127]

Is it a steady flicker similar to being timed? Does it quit when the engine speed is increased?

 

[1997SCEBFEX]

i would have cited alternator based on your original description. is your serpentine belt properly adjusted/tensioned.

agree on the cable ends being checked.
how old is your battery; is it"Fully" charged? does your battery gauge fluctuate moreso at lower speeds/idle like its trying to charge the battery.

sounds like you might have an unexplained draw & or battery.

PanHandler.

 

[rtbrjason]

Thanks for the suggestions. I did spray out the small 2 wire connector with electrical cleaner. It didn't help but will take a more in depth look when it's a but warmer than 10 degrees.

The flicker is steady and actually flickers faster when raising the rpms. Engine was recently torn apart to do all new gaskets from the heads up. While it was going back together I did a new alternator and battery. I've also recently done the tensioner and idler as well as a new gator back belt. All those parts have less than 1k miles.

 

[1997SCEBFEX]

i had my second alternator that induced the same symptoms you are describing; come to find out that it was just a bit "under amperage" compared to what it should be as the voltage regulator packs are plug-n-play for different applications the way they described it to me.

bought a new one for just a few $ more compared to the rebuilt option and running strong for many years now.

That just might be it.

PanHandler.

 

[rtbrjason]

i had my second alternator that induced the same symptoms you are describing; come to find out that it was just a bit "under amperage" compared to what it should be as the voltage regulator packs are plug-n-play for different applications the way they described it to me.

bought a new one for just a few $ more compared to the rebuilt option and running strong for many years now.

That just might be it.

PanHandler.

Good info. Do you know which one you got? I got the "drivewerks" from Advance Auto for $124 or so. All of their options showed as 130amps but it certainly feels like a bad alternator issue. I might be able to swap it under their 1 year warranty, but I'm guessing another of the same model would be just as bad.

 

[stamp11127]

Usually when one of the diodes has failed you will see the lights flicker. When most of these auto parts stores test alternators they are only looking for 12v DC and not AC leakage or pulsing.
I general terms bad diode pack, do the replacement under warranty.

 

[rtbrjason]

I've finally got around to replacing the alternator yet again. I decided to go with a higher amp unit for DB Electronics. I chose their 160amp. While doing this upgrade, I did the Big 4 wire upgrade with 0 awg wire.

I'm still seeing all the lights flickering (mostly noticeable at idle). At this point, it's done this with 3 different alternators and 2 batteries, so something other than that is going on. Anyone have other potential ideas?

 

[Bedrck47]

you may want to check your grounds especially those behind the kick panels
check for looseness, rust etc.
Also check at the frame and on the radiator support

 

[vigman]

Going to put this in the mix as well.. the ALT bolts to the block I ASSUME that connection was wire wheeled ( or other method ) cleaned ? Are the batt terminals OE or aftermarket ?

 

[rtbrjason]

The bolts were not wire wheeled or cleaned, but they didn't look that bad. With the wiring upgrade, I ran a second fused line (0 awg) from the alternator to the battery, as well as a new ground line (also 0awg) that runs right to the back of the alternator.

I will dig around under the kick panel a bit. I do recall digging around there a bit trying to get the courtesy lights to come on with the remote starter/unlock. It's possible one of those connections I tried and removed is wonky I guess..

 

[stamp11127]

Since changing alternators didn't solve your problem it would indicate the problem is in the charging circuit wiring harness or ground connections.
I would do voltage drop tests on the charging circuit next. You'll need a decent dmm for this that can range down to 2-3 volts.

 

[1955moose]

I agree. I had a Lincoln Mark 7 that charged fine till you loaded it with lights,heater, radio, then charging dropped. On Ford cars and trucks they need proper amperage and voltage. Best advice , see if you can buy new alternator not remanufactured. Works the best. Reman alternators and starters have cheap parts from China. They fail or give weird symptoms constantly. For what it's worth like your Daddy said you gets what you pay for.

 

[rtbrjason]

I agree. I had a Lincoln Mark 7 that charged fine till you loaded it with lights,heater, radio, then charging dropped. On Ford cars and trucks they need proper amperage and voltage. Best advice , see if you can buy new alternator not remanufactured. Works the best. Reman alternators and starters have cheap parts from China. They fail or give weird symptoms constantly. For what it's worth like your Daddy said you gets what you pay for.

This is why I tried not one but 2 alternators with the most recent being an upgraded 160amp unit from DB electric. No change to the flickering issue.

I'm not really having much luck with this. I think I might either try some kind of filtering device (expensive) or perhaps run everything through a large capacitor like they use for car stereos..

 

[stamp11127]

When you can, check the battery with a dmm set on a/c volts and take a reading, let us know what it is please. At idle and any higher rpm.

Spent some time digging through the books looking for other possibilities that will cause a flicker other than the alternator. Everything comes back as varying voltage causing the flicker - the alternator is the culprit. The only real way to determine if that is the case is to look at the alternators output wave form on an oscilloscope while in the vehicle.

 

[rtbrjason]

When you can, check the battery with a dmm set on a/c volts and take a reading, let us know what it is please. At idle and any higher rpm.

Spent some time digging through the books looking for other possibilities that will cause a flicker other than the alternator. Everything comes back as varying voltage causing the flicker - the alternator is the culprit. The only real way to determine if that is the case is to look at the alternators output wave form on an oscilloscope while in the vehicle.

I've got a programmer tool hooked up for logging, I'm seeing around 14.3v at idle and 14.1-14.3 while cruising since putting in the new alternator. Prior to that it was a few 10th's lower if anything. I did double check with a volt meter and got the same reading at idle.

My mechanic friend did hook up a fancier scan tool with an oscilloscope built it. There was a very visible spike in the wave as it flickered. Not sure how seeing that in the oscilloscope helped any. It did this with the stock Motorcraft Alternator. It did it with the first replacement alternator from advance which was a reman unit and it is still doing it with the new 160amp so I'm not sure how it could be the alternator. I may have mentioned it above, but with this last replacement, I also replaced all the wiring from the alternator, including the 2 wire plug with a new pigtail.

 

[stamp11127]

What shape did the wave form have? Normal is a continuous series of humps, all being the same in height and the same length.
When you ran new wire did you completely replace the old wire? Specifically the sense wire from the voltage reg to the battery?

 

[rtbrjason]

What shape did the wave form have? Normal is a continuous series of humps, all being the same in height and the same length.
When you ran new wire did you completely replace the old wire? Specifically the sense wire from the voltage reg to the battery?

I don't recall on the shape but can probably get him to hook it up again sometime.

The new wire I purchased was a 3 wire pigtail, where one of the pins has a 2-3" line that runs to a single spade terminal on the alternator. The other 2 wires run from the alternator plug back toward the passenger firewall area to a 2 wire harness clip. That is the new wire I was mentioning. I also ran a 0 awg power wire ( 175 amp fused) from the Main alternator output to the battery.

 

[stamp11127]

I'll look at the wiring diagram later tonight to find the color code for the sense wire. As a test it would be interesting to see if a straight shot from the battery to the sense and another to alt case ground has an effect on the wave form.
A good wave form looks like continuous string of lower case "m".
It would also help to know the high and low voltage reading on the scope. Even though a dmm shows 14.3 volts it may not respond fast enough for the spike to register.