Jacek

I had headlight flickering issue for around 2 years. Had few headlight switches replaced, interim improvement but no ultimate fix, as problem would go back. If you have flickering headlights - here's the ultimate cure recipe. First of all, acknowledge that you're driving Cherokee, which means its all messed up when it comes to electrical stuff, especially if it is old where grounds are not very effective anymore, wiring and/or connectors are corroded or soiled etc. But even if not - the design is far from great, especially matching wiring diameters to power going through - wiring has too small diameter, lots of overheating going on. Then be mindful that the headlight switch has built in circuit breaker in it that affects only headlights. Breaker gets weak with time as it overheats. Result is - power is cut off intermittently, stuff cools down, power is back on and this continues repetitively - hence flickering. Depending on the quality and age of your switch as well as condition of the wiring - it can be minor thing to very drastic. It does gradually go worse with time as the condition of the overheated interiors in the switch is getting progressively worse. Do not believe in simple switch exchange - it will only annoy you and the problem will be back, sometimes not even go away at all. Aftermarket switches vary in quality, and even the best ones will go bad eventually if you do not replace the harness.



What to do?
1) Inspect grounding, especially the one directly leading to the switch itself, there should be one. I will not be surprised if your is not there at all. Sloppy car mechanics and overly confident amateurs underestimate the role of grounding. Fix any issues with grounding.
2) Buy new harness for headlights, there is tons of them out there. It will take the load off the switch and even if the switch condition is not great - it will fix it. I still recommend replacing the switch as you do not know what is its condition inside. Better be safe then sorry, switch is no more than 30-40 USD.
3) Install the harness. It will plug directly to headlights while feeding power directly off the battery hence having minimum current going through the switch itself. You will find YouTube videos on how to do it, easy peasy, half an hour job, unless you will struggle with bunch of rusted screws. It took me 2hrs.
4) Install new switch, you can do it yourself, remember about the grounding.



Note: Do the grounding right. Do not believe people who say that you do not need to strip the paint - it must be pure metal to metal connection to work in optimum way. It will work to some extent without stripping the paint, but you will never be sure when it stops conducting enough charge and starts to cause issues. After you connect - secure the joint with something like copper grease or other conductive grease. It will prevent corrosion and assure long term performance. Apply generously on outside and exposed bare metal if you removed more than you had to.



And - you are done. You have almost life time warranty on your flickering issue and brighter headlights.



Tons of posts with this problem, very little constructive comments to help and resolve this. One other person gives this advice, but not in many threads on this topic. So I'm going ahead and posting this into every applicable thread I can find on the forum.