Passenger side headlight doesn’t work. Both high and low beam on passengers side don’t work. All other lights work including drivers side headlight low and high.
- checked both fuses. 29 and 34. Both are good and getting 12 volts. Car has no headlight relays. Only has fog light relay and both fog lights work.
- Check passengers side headlight harness. Traced the ground to the chassis as it’s close to the headlight and has continuity. For a test, I ran a ground straight from the battery, same result. The ground is good. Checked the low and high beam harness wires. Both are getting low voltage of 9volts at All times. The headlight switch in off position and still getting 9volts on both wires. Turn on the headlight switch and nothing changes, still 9 volts on both hi and low wires. Tested the drivers side headlight harness and all is correct. Getting zero volts with headlight switch off and 12v on low or high depending on switch position.
- If you unplug the headlight switch from the harness all the lights come on except the passenger headlight. Tail lights, parking lights, drivers side headlight all come on when you disconnect the headlight switch. Maybe a hot wire is back feeding into the circuit? The lights should not come on when you disconnect the headlight switch I would think. Also disconnected the dimmer switch, but resulted in no difference or voltage change anywhere. Checked all other bulbs in the car. All are working as should. Disconnected each one and tested voltage, and all is fine.
- Checked some of the wiring down on the harness visually and don’t think it’s a broken wire as I’m getting 9 volts in both high and low beam and the ground is good.
- Tons of hours trying to figure this out and coming up with nothing. Could it be a light output module? If this car even has one? What should I test next? Thanks in advance.
Your Explorer has headlight relays but they're built into the SJB (Smart Junction Box) and they can't be replaced. (if they fail you have to replace the SJB. ((This is your passenger compartment fuse box))
First, you may want to pull the connector off of the SJB and check for evidence of corrosion in the connector and on the pins of the SJB. (that can be pulling down your voltage).
You can also test the pins on the SJB which go to the passenger headlights. If you're only getting 9 volts coming out of the SBJ at the connector (backpin the connection and measure the voltage), it's a good bet that the SJB has to be replaced.
(Incidentally, a dealer level scanner can confirm this and SJB's are expensive. You may want to pay the cost to have any suspicion that the SJB is defective confirmed by having it hooked up to their scanner before replacing it)
All this stuff is "fly by wire". There isn't a wire going from your headlight switch to your headlights. It's all controlled by reference voltages provided to the switches and then the PCM/SJB communicate to control your lights (and everything else). The SJB is like a Body Control Module.
Since this is "driving you crazy" maybe pay the $30 for a 1 year subscription to ALL DATA DIY.
You need to see a pinout for your 2009 explorer to confirm which connector and pins on the SJB control your passenger side headlights.
A quick look on the internet shows that one side of your SJB looks like this. The connector that controls the headlights is this one.
If the connector is the same as a 2007 Escape, the headlight pin numbers and wiring looks like this and you would check the SJB at connection C2280B pins 26&25 for sufficient voltage (12 volts + or_)
So check the connector and SJB pins for corrosion first. If you don't find any use ALL DATA DIY to confirm these pin numbers on your 2009 Explorer and test the voltages at the SJB.
Thank you so much for the detailed info. I didn't know about ALL DATA DIY. I will join and get the diagrams from them and then run your recommended tests. Thank you much