I'm trying to help my son remotely to diagnose electrical issues in his wife's 2006 Civic.

She had noticed flickering lights (instrument panel and headlights). From what I could search, it was a failing alternator.

Last Saturday they went to O'Reillys and they helpful counter guy did the curbside battery test and said the alternator was OK, but the battery was dead. $200 and a new battery. They drove to my brother's house and installed the new battery - now no headlights! Turns out the left headlamp was dead (after about 4-5 weeks since new). Replaced the headlight and all is well.

Last night flickering dash and head lamps returned. This morning AC cut out (I'm not sure specifically, but I wonder if the fan isn't working or if the actual AC won't kick on - why is she using AC in 25F weather).

I'm leaning toward the alternator still not working properly and causing intermittent issues.

My son isn't too mechanically inclined but with Youtube and my brothers nearby, it should be an easy swap.

What say ye?

flickering lights doesn't scream Alt, but it could be.
If the battery isn't draining, it's probably not alt.
If it was checked & charging, shouldn't be the issue.
Sounds like loose connection somewhere in the power distribution system to me (not familiar with Civic). I'd start at the battery cables* & then go to fuse box under the hood. Headlights & HVAC fan are *probably* fed from there, dash lights (in the cluster or standalone) are usually fed from JB/fuseblock under the dash - again, not familiar with Civic specifically.

Most newer cars have a batt terminal clamp, then wires bolted to that, check both for tightness & don't over-torque.

I actually experienced similar symptoms with loose battery cables.

Heater/AC fan speed switch going open. Large current load cuts in and out dimming lights.

Don't worry, it'll burn open pretty soon.

quote:

Originally posted by Some Shot:
Heater/AC fan speed switch going open. Large current load cuts in and out dimming lights.

Don't worry, it'll burn open pretty soon.

The AC compressor or the AC switch?

quote:

Originally posted by Russ59:

quote:

Originally posted by Some Shot:
Heater/AC fan speed switch going open. Large current load cuts in and out dimming lights.

Don't worry, it'll burn open pretty soon.

The AC compressor or the AC switch?

The fan speed selector switch. See if it controls each of the fan speeds well. See if the lights dim while the fan is turned OFF.

Bad ground.

Loose battery cables. Although if they just replaced the battery I would think they where good.

The A/C should come on when the defroster comes on so that's why it gets used in cold weather.

Not sure if the car sits outside or not, but I would check wiring for damage/shorts caused by mice, etc.

Also if the headlight was replaced only a few weeks ago, maybe something was damaged or not reconnected correctly.

If it does it with a fully charged new battery, it’s not the battery or alternator. This assumes testing is done before battery has time to run down.

Check cables, depending on where parked, rodent damage.

Alternator and battery are the electrical supply. If the issue exists with a fully charged battery then it's almost certainly not a supply issue. I'd start working downstream from there - cables, grounds, shorted wires, etc.

I wonder if it could be something in the headlight power circuit (maybe the switch or a relay). Dash lights usually come on when the headlights do so an intermittent on/off in the headlight circuit could cause both problems.

This may not be the answer you're wanting, so here goes.

As noted above, check all cables and wires for cleanliness and tightness, grounds too.

It can easily become a money pit, wasting money on replacing expensive parts without knowing if they are defective and in need of replacement.

I've done this before, on cars trucks boats lawnmowers and generators. I've wasted a lot of money doing so.

After many years of ownership, I've decided it's better to pay a reputable independent garage $100 for a diagnosis to zero in on the problem.

If you don't have one, ask for references, as many as you can get. You want, need, the most honest and decent shop you can find in your area.

Once they've figured out the problem you can decide if you want them to fix it or just take it home and do it yourself.

Best wishes to you, good luck.
.

quote:

Originally posted by DaveL:

I wonder if it could be something in the headlight power circuit (maybe the switch or a relay). Dash lights usually come on when the headlights do so an intermittent on/off in the headlight circuit could cause both problems.

There are comments online about the combination switch (basically, the turn signal and headlight switch in the column) being faulty and causing light issues.

I'll speak with him tonight about plans. And I agree with OKCGene, $200 on a battery and $250 on an alternator.....and still have the issue.

And the irony of the whole thing....I was going to divert my return business trip to SLC to help them out this weekend. They said it was fine so I cancelled my flights and continued home. Got the SOS text this morning. Murphy's Law I guess.

I’m no expert but I do know electrical issues are the worst! Start with the easy stuff. Bad ground wires can cause ALL kinds of funky issues. Find out where they’re at and clean/tighten connections. An internet search should tell you where they’re at on your vehicle. Check for any loose connections on the battery terminals and connectors at the alternator.

Then I’d look for obvious rub through a on wire harnesses and see if anything is rubbed through or chewed through by rodents...

quote:

The fan speed selector switch

Oops. Not the switch itself, but the heater blower resister. Sets the current for the blower motor which is a relatively high-current load on a small car. Thinking that a large current load switching on and off frequently might show up as lights dimming. Same possibility for the rear defrost element and wiring.

Any other high-current options? Heated seats? Groovy woofer?

Check out Youtube, ton of videos on this subject.

quote:

Originally posted by Russ59:
I'm trying to help my son remotely to diagnose electrical issues in his wife's 2006 Civic.

She had noticed flickering lights (instrument panel and headlights). From what I could search, it was a failing alternator.



What say ye?

Chortle, chortle chortle.

quote:

Originally posted by LS1 GTO:

quote:

Originally posted by Russ59:
I'm trying to help my son remotely to diagnose electrical issues in his wife's 2006 Civic.

She had noticed flickering lights (instrument panel and headlights). From what I could search, it was a failing alternator.



What say ye?

Chortle, chortle chortle.

Good catch. My son’s wife.

quote:

Originally posted by Russ59:
I'm trying to help my son remotely to diagnose electrical issues in his wife's 2006 Civic.

She had noticed flickering lights (instrument panel and headlights). From what I could search, it was a failing alternator.

What say ye?

I used to own a 2006 Civic and have many service bulletins I downloaded several years ago. I have one showing how to replace the alternator and another on how to trouble shoot the electrical system. I didn't check, but if you have an email address in your profile I'd be happy to email these to you. Just let me know.

John

My old Volvo had a similar issue, mostly pretty dim headlights were noticeable. Turned out it was a standard weakness in the model. The 'B+' cable, going from the battery + to the main underhood fuse box that feeds everything. It was actually an assembly of four 8 gauge wires. The corrosion was completely hidden from casual inspection. You had to pull it to see anything. Not exposed to weather or anything, just typical galvanic corrosion. It had traveled about 3-4 inches under the wire insulation on the connection inside the main fuse box.

After replacement, everything electrical perked right up. Next time, I will likely make my own from welding cable.

Check voltage regulator. It can also cause all of the symptoms you mentioned by running voltage that is too high (burning things up), too low (things won't function at all), or a combination of the above (flickering, dimming and getting brighter).