Why is my headlight flickering?

[Animal_]

The other day my Jeep started to throw the code P0123 and the driver's side headlight halo started to flicker. Then the engine light came on, started running rough, backfiring, idle was just above 1000, and it wouldn't let me put it in reverse (it would slowly die out). I went ahead and got an OEM replacement for the TPS and changed it out 2 days ago. It has had none of the issues above since... except for the driver's side headlight halo still flickering.

I can't imagine this is due to the P0123 issue arising but it's very odd that they both consequently started at the same time. I went through the forms and didn't find much I also went through all the wiring to make sure there were no cuts or corrosion on any of the negative terminals (I saw that this was one of the main problems people found). Does anyone have any suggestions or know exactly what this could be? I would hate to buy new headlights and then that not even be the issue.

 

[Jerry Bransford]

Start with the flickering headlight first. Since it's the driver's side that flickers that leaves out the switch and wiring leading between the headlight switch and driver's side headlight. The passenger-side headlight gets its power from the driver's side headlight so when it works properly that eliminates the headlight switch and its wiring.

So that leaves just the driver's side headlight connector or its black ground wire to be the cause. Unscrew the black ground wire's crimped connector screw where it screws into to the tub and clean that connector and its tub grounding area and securely reattach it. Then unplug/reseat the driver's side headlight connector a couple times. That should fix it. If it doesn't the headlight is likely the problem. If so you can swap the headlights between the sides to confirm the bad headlight.

The P0123 says the PCM is guessing the Throttle Position Sensor (AKA TPS) is bad. Could be. But what can also cause that problem is the Clockspring connector which is just under the steering wheel which provides the connection between the horn button, air bag, cruise controls etch. The clockspring connector can get electrically dirty inside and send electrical "noise" onto the databus that the PCM interprets as a bad throttle position sensor. If replacing the TPS with a good brand (no store brands for sensors!!) doesn't fix the P0123 problem odds are good that code is caused by the clockspring connector.