Hey guys, I have a 08' Tiburon SE with 80k miles. Bought it a couple months ago, love the thing! Pretty sure nothing has ever been done under the hood except oil changes. Lately my lights have started to flicker/dim, as well as my dash lights. Radio turns off and off randomly while I'm driving, and the gauges seem to reset themselves for a second or too and then go back to normal. I'm thinking its a bad alternator? I haven't checked voltage yet, but I did the old trick of disconnecting negative cable from battery while car is running. The tibby didn't turn off...I turned on all the accessories and everything worked although the flickering continued. There's no year on the battery, so I'm not sure how old it is but I'd say it looks over 4+ years old. I have no warning lights on my dash. Well, lets get to this morning. I'm parked, waiting on someone, with radio and A/C on, as well as headlights, and the Tibby shut off. I started it back up no problem. Terminals to the battery are clean, haven't checked the alternator hook ups since they are a ***** to get to. Should I bite the bullet and just swap out the alternator? This is my daily, I drive 80+ miles a day and don't want to get stranded. Thoughts? Thanks in advance!
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Possible bad alternator?
Tuscani1309
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Yes. In the picture it looks OK.
Yeah, that's the one. Make sure it has good pin tension & that it isn't getting too warm. If it's fine check the 50A "BATT" Fusable link in the E/R Box in the engine bay.
Does your blower motor change it's speed at all with cluster getting brighter & darker?
Edit: also, it sounds dumb, but check your battery terminals. poor terminal contact can cause a lot of weird issues. Also check the battery ground cable. It bolts to the body next to the battery & there should be less than .1V difference between the battery terminal & it's body mounting point.
Does your blower motor change it's speed at all with cluster getting brighter & darker?
Edit: also, it sounds dumb, but check your battery terminals. poor terminal contact can cause a lot of weird issues. Also check the battery ground cable. It bolts to the body next to the battery & there should be less than .1V difference between the battery terminal & it's body mounting point.
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Gotcha. Passed the info to my mechanic. No. It’s very weird when it does it. It may do fine for a week, then it goes on a spell for a few days. At idle if I turn on the ac or roll down windows voltage drops and sometimes it even makes engine die. But starts back up again.
That definitely sounds like a main power feed problem.
Check battery connections, check main power feed cables, check the E/R Fuse box for corrosion.
Voltage drop tests are your friend in this scenario. That's where you put your multi-meter to 20VDC, put one lead on one side of a cable and the other lead on the other side. If you have a voltage drop you'll see a reading on your multi-meter, ideally you want to see less than .05V on any connection.
For example, if you want to test the battery cable from B+ to the E/R Box, you would put some kind of load on (for example the blower motor on high), put one lead on the B+ post, and the other on the E/R Box B+ block. If you see 0V then you're good. If you see .1V or greater then you have a poor connection. the larger the difference the worse it is.
These poor connections can be "fine" when they're not loaded too bad, but as soon as you put a large load on the circuit (example: power windows) the excess current can cause the voltage drop to be so great that you're losing 3 or 4 volts over the poor connection.
My primary concern is the E/R Box because it feeds the power to everything. We can rule out the alternator because if it wasn't charging the battery would be dead & the car wouldn't restart. therefor, I believe either you have a bad ground connection that's dropping the effective voltage the system can use, or the E/R Box has a bad connection to the battery, which makes the effective voltage for everything (including the voltage gauge in the multi-gauge) get lower the more load you put on the electrical system.
Diagnosing this requires some basic electrical skills, but should be pretty easy to do even with youtube mechanic skills. If your mechanic can't figure this out I would suggest taking it somewhere else. Here's a quick 6 minute video that explains how to do a voltage drop test:
I've heard of people having issues with the B+ battery terminal, it would be worth checking that for corrosion / connection issues.
Check battery connections, check main power feed cables, check the E/R Fuse box for corrosion.
Voltage drop tests are your friend in this scenario. That's where you put your multi-meter to 20VDC, put one lead on one side of a cable and the other lead on the other side. If you have a voltage drop you'll see a reading on your multi-meter, ideally you want to see less than .05V on any connection.
For example, if you want to test the battery cable from B+ to the E/R Box, you would put some kind of load on (for example the blower motor on high), put one lead on the B+ post, and the other on the E/R Box B+ block. If you see 0V then you're good. If you see .1V or greater then you have a poor connection. the larger the difference the worse it is.
These poor connections can be "fine" when they're not loaded too bad, but as soon as you put a large load on the circuit (example: power windows) the excess current can cause the voltage drop to be so great that you're losing 3 or 4 volts over the poor connection.
My primary concern is the E/R Box because it feeds the power to everything. We can rule out the alternator because if it wasn't charging the battery would be dead & the car wouldn't restart. therefor, I believe either you have a bad ground connection that's dropping the effective voltage the system can use, or the E/R Box has a bad connection to the battery, which makes the effective voltage for everything (including the voltage gauge in the multi-gauge) get lower the more load you put on the electrical system.
Diagnosing this requires some basic electrical skills, but should be pretty easy to do even with youtube mechanic skills. If your mechanic can't figure this out I would suggest taking it somewhere else. Here's a quick 6 minute video that explains how to do a voltage drop test:
I've heard of people having issues with the B+ battery terminal, it would be worth checking that for corrosion / connection issues.
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Alright. I'm picking up the car from my mechanic today, I need it back and they probably haven't been able to solve it so I will have to do it on my own. I will post some more videos of what is doing to see if there's any more suggestions. I'm mechanically inclined but anything electrical I've never done before but doesnt seem to hard.
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No, like I said its a very weird problem. Car acts fine all week and the randomly has those voltage drops, and then it acts fine again. Headlights and interior lights do flicker constantly once it acts up...I remove the negative from the battery, reconnect it, and it acts normal again for a week or so.
The reason I think your issue is further up the chain is because the blower motor has it's own dedicated power feed straight from the E/R Box. If your blower motor is getting weaker when you're experiencing those issues, that means the problem must be in or before the E/R Box.
Disconnecting the negative battery cable could be causing an intermittent poor connection to temporarily make good connection. I would highly recommend doing the following tests:
•Measure voltage difference/drop from Battery negative post to the body ground.
•Measure voltage difference/drop from Battery positive post to the E/R Box positive post and/or one of the fuses near the fuse puller.
The electrical system needs to be loaded for those tests. I would recommend putting the blower motor to high and turning on your headlights. It would also be best to do these tests when the problem is acting up.
Disconnecting the negative battery cable could be causing an intermittent poor connection to temporarily make good connection. I would highly recommend doing the following tests:
•Measure voltage difference/drop from Battery negative post to the body ground.
•Measure voltage difference/drop from Battery positive post to the E/R Box positive post and/or one of the fuses near the fuse puller.
The electrical system needs to be loaded for those tests. I would recommend putting the blower motor to high and turning on your headlights. It would also be best to do these tests when the problem is acting up.
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Well I just got the car from the shop. They weren’t able to figure it out. So it’s up to me now. This is so frustrating!!
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Would any of these be a reason of why it’s doing what it’s doing? I can order new cables if needed or sand these out. The actually terminals that are sitting on the battery post are clean and corrosion free though. Does the outside matter? Never had trouble starting the car, just the intermittent ongoing issue I been having as stated.
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The minor corrosion on the outside is a nonissue.
Please don't sand plated electrical stuff, degrease if needed and then wire brush or scotchbrite.
Good connections are clean, flat and tight. Sometimes, on bolted connections, when you just get snug, twist the connection back and forth to mate the parts, then tighten.
Please don't sand plated electrical stuff, degrease if needed and then wire brush or scotchbrite.
Good connections are clean, flat and tight. Sometimes, on bolted connections, when you just get snug, twist the connection back and forth to mate the parts, then tighten.
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Yeah , just did voltage test and it all checks out. Again, car is running fine for now, but I daily it 166miles to work and it likes to act up on the highway every now and then while I’m doing 80..thanks for all the help guys I appreciate all the suggestions and help yall have provided.
First thing I notice is both your positive and negative battery terminals are cracked. I would get that replaced to rule them out. They're cheap & relatively easy to replace, just make sure to get a style you can bolt the three cable bus bar to.
Edit: For context:
The three cables on the positive side from top to bottom as pictured:
Top: E/R Box B+ feed
Middle: Starter B+ feed
Bottom: Alternator B+ charge
But seriously, get those battery terminals replaced ASAP. Poor connections at the battery can cause all kinds of wacky problems, and both of yours need to be replaced. For the ground, I think you can buy 1ft cables from parts stores & replace the terminal/cable in one big unit. Make sure you clean the paint off the body on the grounding point if you do that. You should be able to find a generic post for the positive side.
Your engine bay looks incredibly clean & corrosion free. Not often do I see a battery tray that isn't rusted to bits. Makes me second guess your issue being corrosion related.
Edit: For context:
The three cables on the positive side from top to bottom as pictured:
Top: E/R Box B+ feed
Middle: Starter B+ feed
Bottom: Alternator B+ charge
But seriously, get those battery terminals replaced ASAP. Poor connections at the battery can cause all kinds of wacky problems, and both of yours need to be replaced. For the ground, I think you can buy 1ft cables from parts stores & replace the terminal/cable in one big unit. Make sure you clean the paint off the body on the grounding point if you do that. You should be able to find a generic post for the positive side.
Your engine bay looks incredibly clean & corrosion free. Not often do I see a battery tray that isn't rusted to bits. Makes me second guess your issue being corrosion related.
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Also, mechanic said he checked the bcm power feed cable..but then again I didn’t see the owner u
gotcha, will look into getting new ones. Yeah it’s an Alabama car, we don’t really have rust down here. I don’t have any rusty bolts or anything like that.
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That cable looks fine judging by the picture you provided, but they only really start to look bad after they've been bad for a while.
Like I said earlier, if your blower motor is fluctuating with everything else then we can rule out that BCM power feed cable. The blower motor is powered from the E/R Box directly, so if it's being affected then we know the problem is upstream from the BCM.
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Blower motor is fine. So if battery is good, grounds are good, terminals are good, alternator is good, bcm is good..what else could it be? It’s like a ghost attacks my car every other week and makes it go haywire.
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That’s why my mechanic had such a hard time, half the time he had it it wasn’t doing anything it was acting normal. No check engine lights, car ran perfect, was throwing no codes..
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Now that you mention it..when it does act up, everytime I turn on the a/c it likes to trigger it/make it worse. Last week when it was acting up real bad, I had it in the garage and I was messing with the a/c and it was triggering it really bad to the point it shut the car off. But half the time it acts up even when a/c is off..so idk. I took a video of that day in about to post it.
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Yep, so the blower motor is definitely affected.
My primary suspicion is the cracked ground terminal. the positive should also be replaced since it's cracked, but that ground terminal has a really big crack near the nut. Ether of those terminals would affect everything like in that video.
Turning on the blower motor will cause a huge spike on current on the electrical system at first that can & will make a bad connection act like this. The fact that everything is affected tells me it has to be one one of those big cables in the engine bay.
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