Help me..Headlight Cycling/Charging Problems...

Hey, guys... long time no browse...

I was kinda HOPING someone MIGHT have had problems like mine and they could shed some light on this.

Here's the problem;

a few months ago, my 92XJ (HO) started exhibiting some odd behavior. the headlights would turn off intermittently - it SEEMS to have gotten worse over time (more time off than before on average) - but ANYWAY, a friend of mine told me it was a classic sign of a bad alternator - this made SOME sense to me - and since I'd been meaning to upgrade for several years, I decided to call Mammoth Power Systems and order one up (very EXPENSIVE and SLOW service by the way...). I got a 160amp unit (nippon denso) for $320.

AT ANY RATE, the swap was an absolute BITCH (much grinding and filing to make it fit!) but I still have the exact same problem as before; SO... the question NOW is...

Is it possible that I have a bad voltage reguator (I thought this was INSIDE the alt) or a bad ground?? What would cause this sort of cycling??? My battery is frequently near dead (optima yellow).

I DON'T know WHAT to do... please help if you can...

sincerely, J.

I would start by cleaning all the grounds and do craigh's wiring upgrade, it sounds like something is overheating.

Yeah... I looked at the wiring upgrade... but it's a bit more complex than he describes... there's a junction with a small box between the pos on the alt and the main fusebox/distribution junction - there's a few different wires coming and going from this. good suggestion though... any other ideas?

I would for sure put in heavier ground wires and get the mounting points nice and clean with plenty of anti-corrosion compound. Throw a charger on the battery, engine off and cold, headlights on, hood open and start looking for hot wires. It could also be the plugs on the back of the lights themselves, they corrode over time and need to be removed and cleaned with a very small file or burnishing tool, then reassembled with dielectric grease. Next to anti-seize, dielectric grease is the next most used stuff I keep in my tool boxes.

There is a multi-way connector in the left fender behind the airbox. The wires have a tendency to corrode there where they are crimped in.

Is it just the headlights blinking on and off, or all the lights? If its just the headlights, there is a circuit breaker built into the headlamp switch that cycles the headlights on and off if too many amps are drawn. May be just a bad switch, or do you have higher wattage headlights or extra lights running through the switch?

NexJ,

I have had the same problem as you are describing. For me, it was the headlight switch. Not to easy to get out, but solved the problem! The first time this happened the Jeep was about 2 years old, yeah first time. I took it back to the stealership and it took them three times to actually narrow it down to the headlamp switch. So when it started happening again, about 3 years later, I just swapped the switch out again. Hope this helps out.


Alex