Electrical

2007 Hyundai Sonata after caught in small flood water to floor level now have no tail or marker lights all others work. No power windows but locks work. Have looked at wiring diagrams and do not see any common components. Have tested and no power to passenger compartment fuses but have power at engine compartment fuses on both. Any insight or direction on next steps. Looks like relays are in between fuses and are built into fuse panel itself. Beginner level keep advise simple thanks.

Alrighty, we're gonna keep it simple! We'll attack the lights first, and circle back around to the windows if needed. :silly: First off, 2.4L or 3.3L? Not sure that it matters for where we're at, just good to know for reference.

Two checks:

1.) I know you said you checked fuses, but please verify that the TAIL LAMP FUSE (20A) in the underhood fuse box will light an incandescent test light on both terminals with the key on and headlights on. A multimeter reading with the meter connected to B- will work, too.

2.) If the above is OK, check the TAIL LH (10A) and TAIL RH (10A) fuses in the passenger compartment fuse box the same way. Again, I know you said you found no power at the passenger compartment fuses. We need to know about these two, specifically.

Let me know what you find.

Power at 20 amp under hood fuse no power at both 10 amp fuses passenger compartment. 2.4 liter

Excellent. Here's the tail lamp diagram, for reference:



We can figure that the Tail Lamp Relay isn't working, since the TAIL LH and TAIL RH fuses are dead.

Next step is to find the Tail Lamp Relay in the passenger compartment fuse box, and remove it. Using your test light connected to B-, gently probe all four pins. Two should light.

I believe the relay is built into fuse panel junction box how do you test that?

Man I hope it isn't! :lol: 'Cause that'll make our lives a lot harder.

According to this diagram, the Tail Lamp Relay is on the back side of the passenger compartment fuse box.



Have a look and see if this matches what you're seeing.

The basic theory for what we're looking for at the relay is explained in this video:

I see all the electrical plugins do not see anything that resembles a removable relay for any of the relays shown in diagram. What next?

That sucks. :silly: The next best thing is to find pin 8 at the I/P-B connector at the passenger compartment fuse box. Black/orange wire, according to the diagram. I highlighted the pin that we want:



I dunno if you have a test light or DMM to work with. :silly: In simple terms, we want to see 12V at that pin with the headlights off, and 0V with the headlights on. This pin is the BCM's control of the relay.

Please check this pin with the key on, headlights on and headlights off, and let me know what you find.

How do you access the I/p-b plug it is not visible?