QuestionQUESTION: "Hello,
Full History: Hyundai 05 Elantra sedan
-replaced OEM head unit with Pioneer DEH-P3100 (bought harness and sodered/etaped all connections solid.)
-replaced front speakers with rockford fosgate same dim. (stuck on a few bass blockers)
-left OEM back speakers alone but stuck on bass blockers.
ran peachy for a year or so.
-installed Pioneer IPOD interface CD-IB100II behind head unit (installed correctly) had to coil excess cables yellow/black power bit messy but secured to frame. Used DIN connector from CD-IB100II to back of head unit.
ran peachy for 3 months with Ipod line in, then crap hit fan.
I lost sound from right front speaker, then later left back speaker, now just down to right rear, and if I bang on head unit or hit bump in road the left front comes on for a few seconds.
Troubleshooting--cut out bass blockers in back (just cause) continuity check good from back of head unit harness to all speakers. Tested new working speaker on bad OEM rear left speaker terminals with no result. Tested all speakers installed, they are good.
Visited various forums to check if it was an amp issue, only to find my car has NO amp! ...discovered after tearing out half my trunk in the place the shop manual said it'd be.
So, guess Ive got a "low-line" system?
Bottom line is I just want sound in my speakers back, I know they all are good. Sound dosent have to be great, just needs to be there.
Looking for a no/low cost solution. Any Ideas? Please?
btw-the audio fuse in passenger compartment is fine.
ANSWER: Hi Fred,
Given your description, and the various troubleshooting you've done, my primary suspect would have to be the head unit at this point. One final test, if you have a multimeter handy: set it for AC volts, and probe the (+) and (-) speaker wires of each wire pair at the back of the head unit. A working speaker output should show varying AC voltage that increases and decreases with the music volume. (An analog meter with a needle, or a digital meter with a bar graph feature, works very well for this; you can watch it move in time with the music). If you see AC voltage behind the head unit, but hear no sound from the respective speaker, then there's either a problem with the speaker or a broken connection in the wiring between the speaker and head unit. You can repeat the AC voltage test at the speaker terminals; if you find AC voltage at the head unit, but not at the speaker, then there's definitely a broken connection. However, I suspect you'll find no AC voltage at the head unit outputs for the non-working speakers, which means the head unit is defective.
A couple notes: I don't think I've seen an Elantra with an external factory amplifier; they may exist, but it's not common. In most Elantras--and most other Hyundais--the factory amplifier is built into the head unit. Also, my reference shows that your vehicle includes 6-1/2" speakers in the front, and 6x9" speakers in the rear. If this is correct, I don't think I'd use bass blockers, as the speakers should be capable of handling the full audio range without much of a problem--and in any case, the head unit has a built-in high pass filter option. This works the same as a passive bass block, but it's much more effective. (Note--there are actually two different Pioneer DEH-P3100 head units, from several years apart; I assume you have the newer DEH-P3100UB model, with the front USB port).
Hope this helps!
Brian
---------- FOLLOW-UP ----------
QUESTION: Hey Brian, thanks-very informative.
My suspicion is also the head unit. I have the older P3100 model and have had it for over ten years now, it's been in two different cars. Just thought they go completely dead when they go bad--not one speaker at a time as is the case.
However, I may try as you suggest above, although I have established continuity (with head unit removed) from harness to each pole of non-working speaker terminals. This tells me the head unit is not supplying working AC voltage to speakers--but please let me know if I am wrong in this assumption.
To clarify--
"set it for AC volts, and probe the (+) and (-) speaker wires of each wire pair at the back of the head unit"
When you say "at the back of the head unit", i can't probe these because the headunit harness (or the next thing in line after the headunit) needs to be plugged into the headunit to test for AC voltage, right? I mean the headunit need to be playing music. Please forgive me if I'm not quite getting that, maybe you could be a little more specific...
"You can repeat the AC voltage test at the speaker terminals"
I follow you logic here, and all I have tested for is cont.
To do this properly, do I take the red AND black probes from the multimeter to a SINGLE terminal (+) at the speaker? OR red to positive, black to neg.
As a final note, is it possible that connections just arent meeting up at the harness? (i.e. OEM harness to pioneer harness, Or pioneer harness to back of head unit) Maybe a pin is sticking or loose or something, although I visually inspected them.
Also, thanks for the tip about the high-pass filter over bass-blockers, it never occured to me. Think I got suckered in to getting them at a bestbuy years ago...
ANSWER: Hi Fred,
I agree that the continuity testing is pretty conclusive, and doing AC voltage testing may be overkill; but I've always used it as the most informative troubleshooting test. In the simplest terms, it's the head unit's job to produce an AC output, and the speaker's job to convert AC voltage to sound waves; so the presence or lack of an AC voltage immediately tells you which component is falling down on the job. If there's AC at the speaker terminals, and the speaker isn't moving, then it's a bad speaker; if the head unit is on and playing, but there's no AC on the output, then it's a bad head unit.
I agree that it's unusual for a head unit on one or more speaker outputs, rather than all the outputs at once, but it's not unheard-of. A loose pin at the radio plug might be the culprit--but you've got multiple speakers not working. There's no one single pin that could affect two or three speakers at once; you'd need multiple loose pins. At that point, an internal defect seems more likely.
Usually, when a head unit is wired into a vehicle, there's enough slack on the harness to allow you to pull it out of the dash cavity but keep it working. That's what I meant, when I talked about testing for AC voltage at the back of the head unit: pull out the deck, and test the wires at the back while the unit is playing. Granted, this is easier in some cars than others. I have a set of test clips for my multimeter that make it easier to test wires, as they include a "bed-of-nails" feature that lets me clamp on the wire without stripping or cutting it. However, you might be able to use the probes to touch the pins directly in the radio plug, or insert them into the crimp connectors (if you used crimps for the wire connections). To test for AC voltage on a speaker output, you'd put one terminal on the positive speaker wire, and the other terminal on the negative wire (the polarity of the probes doesn't really matter for this test). However, you can also put the black probe on chassis ground--the deck chassis itself should do just fine--and probe each of the wires in turn. You'd still see AC voltage this way, but it will be a lower level than if you tested the two wires together. This can be an easier testing method for someone trying to juggle an operating radio and a set of test leads.
Hope this helps!
Brian
---------- FOLLOW-UP ----------
QUESTION: Thanks again,
performed AC test and no voltage, even at working speaker? (weird)
Anyway popped in a new 3100UB head unit (open-box best buy !$50!)
and everything fired right up.
Hope this thread hopes any would-be troubleshooters out there...
As a final note, this time when installing new head unit, I left out the blue wire, could have been a problem in the first place.
Anything else I can do to keep this from happening with my new head unit?
AnswerHi Fred,
Sorry about the wait in getting back to you on this.
From the sound of it, you got at least ten years of service from your old head unit, which is about as much as one can reasonably expect. I doubt that the blue wire was responsible for the problems with the old head unit. As long as the speakers are wired correctly, and you're not using speakers with a lower load impedance than the deck is rated for, then I don't think you need to worry much about the new unit.
Hope you enjoy your new CD player!
Brian
