Chick-N-Picker

1989 XJ 4.0 auto 4x4 115,000 miles.

I've got some wiring issues with my headlights, and turn signals. Basically think it may be coming down to my headlight switch needing replacing (and a bulb or two). While I replace it, I am going to upgrade the harness.

Can somebody link me the upgraded harness? I found some older threads but the links went nowhere. Pretty sure they can be had for cheap on Amazon or Ebay ($20) but want to make sure I get the correct harness that is an upgrade.

Also when I change the headlight switch, I'm assuming the harness connector at the swirch may be melted to some degree, like I have seen in pictures. Any links or parts number for that connector harness? Maybe I'll get lucky and no melting but asking ahead of time.

I will also be replacing both headlights and some bulbs on the jeep.

Edit: I have already recently (6 months or less) cleaned both the dipstick ground and firewall to valve cover ground. May clean them again just to keep them extra clean.

Now on to symptoms if you wish to read this: Basically if I turn on my headlights at night. Inside on the dash the turn arrows can be lit up to varying degrees of brightness. It also causes my turn signals to not work when like this. It can be one or both. Also the lights that light up the 2H 4Hi 4Lo will come on sometimes, sometimes not. On the head light switch I can not dim the dash lights. If I twist it to the left to dim them they just go out. I think that covers it as short as possible.

Chick-N-Picker

Guess this is the harness, if not, correct me. They have one for $25 and another one for $17. Don't really look any different.

boxburn

That harness looks like it should do, it doesn't mention it's trigger but you need a positive trigger harness. I've heard of some that are negative trigger.

One bad point, there's a review that say the wiring is under-rated with a picture of the OEM gauge wiring used on their vehicle and the harness' wiring and the difference looks a lot. Whether or not their OEM is overkill I can't say but just be aware of that.

ijeeep

Go for the kit with sugar cube relays and the heaviest gage wiring you can find. No pun intended but the difference will be like day and night. Besides restoring the full 12.8 - 13.2 volts to your headlights ( I'll guess your only getting 10-11 volts now ) the wires will have the extra amperage capacity to run higher wattage lights off road. The headlight switch will only carry the ( low amp ) load of operating the headlight relays instead of the full load of the lights. That makes headlight switches last indefinitely.

ijeeep

AC current flows through the whole of the wire. DC current flows along the surface. Heavier gage or higher strand count than factory are the way to go. The factory headlight wiring was barely adequate when new on the assembly line. After 30 years, not so much.
​​​​​​​ Over time in normal conditions our wiring lightly oxidizes inside the insulation to some degree. Resistanc goes up and voltage at the lights is down. Replacing the wiring from beginning to end is a huge PITA. The upgrade kits are the faster cheaper easier better and longer lasting solution for our 30 year old headlight harnesses.

MaskedMallard

1). What happens during the day, if you turn your headlights on?
2). Sounds like a grounding issue. I can't remember if there was a fix to run an extra ground wire from the instrument cluster to some sheet metal near by. Maybe I'm thinking of a different car... I'm not saying this is "The Fix", but it might be a good place to start. Failing hazard relays also do some strange stuff.
3). Sounds like you have a failing bulb (KISS Theory). Just make sure you replace it with the recommended bulb number, or you might start melting the surrounding plastic & bulb holder.
4). Sounds like it's time for a new headlight switch.

Chick-N-Picker

Delete.

Chick-N-Picker

Well I found one on Amazon for $7.99 (marked down from $15) and seems to have thicker wire, at least on the red power wire.

The reviews are about the same as all the others. 4.5 stars. Says last one in stock. Last time I ordered something that said last in stock it never showed up haha.

EDIT: Said screw it and ordered one. Should be here tomorrow or the next day.

boxburn

Uh oh, relevant review time.
At least they got it to fit in the end.

Chick-N-Picker

I read the reviews and did not see that. In fact, I seen people saying they used for their Cherokee. And the description said it fits Jeep Cherokees. I did not see the review you quoted. Must have scrolled by too fast.

EDIT: I cancelled it. Hopefully I stopped it before it shipped out. Why does nothing ever go right for me? It has started to become discouraging.


EDIT AGAIN: Got an email it was too late to cancel. So now either hope it works, make it work, or do a return. Eff. Please work.

MaskedMallard

It might be easier to pay a little more money & atleast, perhaps get direct support if you have trouble with your install. Check these guys out.

https://www.ksuspensionfab.com/store...Harness.html#/

Chick-N-Picker

Got the new harness yesterday.

I do have a few more questions before changing everything.

1. Does it really matter where I get thr new headlight switch (Oreillys, Napa, etc) or are they all about equal?

2. Where are all the grounds in regards to the headlights, turn signals, etc? I know about the dipstick and firewall grounds, are there anymore I should clean and check? I realize I may find these as I go along but figure it smart to ask ahead.

3. Do the 89's have a flasher relays? If so is it two, one for signals and one for hazards? They are the little cubes correct? And then don't they also have a little round one too? (Reafing contradicting info about all the relays)

4. Can a blower motor that is going out have any effect on the headlight switch, headlights, turn signals?

robsjeep

dc power does not just travel on the surface, if that were true, dc wires would be made extremely thin, but very wide for best current capacity, but that is not the case.

corrosion of wires does reduce the wire cross section of low resistance metal, and corrosion can go deep into the cross section, making a very good resistor out of portions of the wire.

on the 1990 xj the headlamp ground is on the inner driverside fender well, near the aircleaner. make sure that ground point is good. adding relays can help a lot.

Chick-N-Picker

Did the head light harness upgrade today and of course it didn't go right.

Bought a new right side head light.
Left side head light had Lo and Hi beam before.

Now my left head light only has Hi beam. No Lo beam. Unplugged it and checked the connector. Re-plugged it but still nothing.

I didn't change thr head light switch but seeing as how the lefr had both Lo & Hi before the new harness I'm pretty sure it is something with the harness. What should I check for.

I am driving on a dead tag because I am having head light and turn signal issues. Nothing is ever simple to fix for me. Effing ever. I borderline want to sell even though I love Jeeps.
Actually I borderline want to give up on life.

Edit: It was the head light. Switched it over and put the new one in it's place and it works on the left side. Put the old one on the other side and it still didn't work. Makes zero sense, considering it worked before.

At least I have head lights. Still didn't solve all my problems, like why the eff my right turn signal arrow lights up in my jeep when I turn my head lights on, but doesn't light up outside the jeep and will not blink. Going to change my head light switch and see where that goes. I know after 32 years of the stock set up it needs to be changed.

cruiser54

CRUISER'S MOSTLY RENIX TIPS

HEADLIGHT HARNESS UPGRADE

NOVEMBER 17, 2015 SALAD 63 COMMENTS

It’s easy to install a supplemental headlight harness.

From the factory, the voltage to the headlight bulbs travels from the battery, through connectors, inside the cabin, to the headlamp switch, and then back out to the lamps via undersized wire and more connectors. It’s not uncommon to find only 10.5 volts at the lamps.

The supplemental harness is installed so that it provides battery voltage to the lamps and is just triggered by the factory wiring. The result is about 35% brighter headlamps and headlight switches that don’t melt and burn out.

Here’s a link to a harness on ebay: http://www.ebay.com/itm/CERAMIC-H4-H...-/330997592807

Absolutely plug and play:

• Remove grille and headlamp bulbs. I fed my harnesses from the passenger side starting between the battery and the back of the headlamp housing, over to the driver side.
• Plug the driver side bulb into the new harness.
• Attach the new harness’s ground wire under one of the small bolts on the radiator support after scraping the paint off under it.
• Attach the harness to the existing harness behind the grille working toward the passenger side.
• Plug the new harness plug into passenger headlamp.
• Plug original headlamp plug into receptacle on new harness.
• Attach the ground for the passenger side just like you did the driver side under a radiator support bolt.
• Attach relays with provided bracket on the passenger side inner fender.
• Connect power wires to battery.