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04 Sonata weird electrical problems

05-18-2009, 12:18 PM
I have a '04 Sonata 2.7 w/ some strange electrical problems. They aren't show stoppers but a bit annoying. I got this car back from my ex (long story, please don't ask) and have found the following problems:

Returned to me w/out the aftermarket radio. Hooked up the factory radio only to find that it does not work. Initial inspection revealed three (3) wires severed in the radio wiring harness. Nice. So illumination works but the radio doesn't, even after splicing the severed wires back together. It is the "premium" system with 6 speakers, amp, CD, cassette (for a '04 - amazing), CD changer controls (but no changer) & power antenna.
Trunk lid open indicator (in the instrument panel/dash) light constantly on. The plunger switch in the trunk latch jam makes the indicator dim briefly when depressed. The trunk light also does not work even though the bulb is fine. Strangely, if I remove the trunk light the dash indicator goes out. I think this contributes to my next problem.
Remote door locks no longer function. The light on the remote flashes indicating it is working properly (doesn't need a battery) but the system does not work. The power locks work fine.
The dome light does not work when any of the doors are opened. The switch is in the "Door" position but does not work. The "On" & "Off" positions work as expected.
How does the trip odometer work on these things? Trip A & Trip B reset when I start the car. How do I get it to just tally miles like a regular trip odometer? I usually reset trips when I fill up the tank so I can calculate my mileage.

I've checked all fuses and relays that I can think to check. I called a dealer and was told a computer diagnostic would be necessary. For some reason I just don't think that would help but maybe someone can prove otherwise (?). If more detail is required I would be more than happy to provide. If this seems like a train wreck then please say so just so I'm not left here hangin' on to an empty thread.

Any help is appreciated and I thank you in advance.

05-21-2009, 03:08 AM
Did the severed wires look like they were done on purpose? I'm a mechanic and given the first part you wrote about just getting it back makes me think someone went in there and cut and/or switched some wires around for fun. Does the trunk open light on dash go off when the trunk is open? If not I would follow the wires and look for a rubbed through wire, it sounds like it is shorting to ground, which could also be in the trunk switch its self which would explain why it goes off when you pull the bulb out, that would open the circuit. As for the door open dome light check the peg in the door it should be at the front or hinge part of your door. when you open the door it should pop out closing the circuit and allowing the light to come on, so if it is not popping out that would cause that problem, you can lube it up and get it to work again. Sorry never had to work on any remote door unlocks but again I would check for some damaged wires or something covering the the remote sensing device. Let me know if any of this is helpful, I have alot more you can check if it doesn't.

09-18-2010, 11:57 AM
I have a 2002 Sonata GLS with similar problems. The main one is with the doorlocks. The doorlocks will lock both with the manual button and the keyless entry FOB, but will not unlock with either. When I press the UNLOCK button on the FOB the front and back lights flash, indicating the system is receiving the signal to unlock the doors, but nothing happens. If I unlock the driver's door with the ignition key and press the manual UNLOCK button, still nothing happens. If I press the manual LOCK button on the driver's door, all doors that are unlocked will lock. I suspect that fixing the problem with the driver's door UNLOCK button will also fix the keyless entry problem. Any opinions out there?

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