2006 Clunking from rear
 

I have a 2006 Sonata, i bought the car used back in 07. Ever since I have owned it it has made a clunking sound coming from the rear. It is definitely not the same fuel sloshing sound. This is sound becomes more pronounced whenever I go over bumpy road. It almost sounds like rear shocks or shock tower. I have taken it in and the dealership found nothing. Any ideas would be great...

Also I noticed at night when the lights are on, the heater is on as well as the radio. My headlights dim. The service guy at the dealer told me that he headlights do that????? Any ideas would be welcome. To me it sounds like a bad ground somewhere.


Thanks

Replace the complete positive battery cable assembly,,, known problem, part number change a while back...

Remove the ground cable where it bolts to inner fender, grind paint off to bare metal, apply anti-sieze, re-install cable end to body.

At the left frame rail adjacent to the battery tray (must remove the tray),, you will see a large staimless braided ground strap, remove that end, grind paint off to bare metal, apply anti-seize, and bolt the cable end back to frame rail.. re-assemble all...

Using DVOM, verify 14.2-14.5 volt running, turn on headlights, watch voltage, add another item, and so on, voltage should pretty well stay steady 14.0 +/- volts.

I don't think I would just replace the positive battery cable without performing the diagnostics first. There is a TSB for a voltage drop issue which describes a number of tests to be done to pinpoint the problem(s). It could be the positive battery cable, negative battery cable, ground straps or grounding points. All of them should be checked as per the TSB to make sure you are actually correcting the problem.

Done 3 myself already... been couple other through shop that other techs have done.

Symptoms:

Fan speeds up/down, radio cuts in and out (audio goes away, but display stays where you had it set), dash lights dim when step on brake pedal, or see head lamps dim..

You want to volt drop, put test lead on negative battery post, with engine running, touch red lead battery positive post, note voltage,, then touch to the alternator post (kinda tight to get to), note the voltage. Go into the engine compartment fuse block, see them 2 studs with smaller cables on them .. 1 has red tape on cable, other has blue tape, touch each post and note voltage... while in the red post, flex the cable assembly, se if voltage goes up/down..

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