electrical demons! please help a newbie

Hey Everyone,

Newbie XJ owner having serious issues that I would really appreciate any help. Bought my ’89 XJ Limited about 3 months ago, and have been loving it. Had a problem as of this weekend.

Parked the jeep last Tuesday, the started it up Friday. As it was getting dark, I flicked on my headlights, only to find they were not working. A little more diggin’, and find that it’s not just the headlights. Here is a list of the things that have suddenly gone POOF:

-headlights
-parking lights
-instrument cluster lights
-reverse lights
-brake lights
-hazard lights

The weird thing is that the turn signals work when the car is running, however, they don’t work in conjunction with the hazards.

I have searched the forums like crazy for answers before resorting to asking for help. I’ve tried to check as many grounds as I can find (have really only found the one in the engine back near the washer reservoir), checked the fuses that are located in the drivers side area, replaced the headlight switch, (man that was a PITA), and just generally poked and prodded as much as I could. The only fuses I could find seemed to be fine. As for the taillights, I removed the housing to check the bulb, which is also fine.

Does anyone have any suggestions on other things I should check? Am I missing something? Which relays are associated with the lighting? Is there a way to check to see if a relay has gone bad? Is there something that would go bad that would cause all these systems to go out?

I’m pretty good with cars, however, am completely new to the world of jeeps. Any help you guys can offer me would be greatly appreciated, as it would let me keep driving!

Thanks in advance….

IMSC you have at least three different fused circuits out there. If I remember I'll pull my 87 FSM and see what I can find common on all of them.

alot of what you mention go`s through the ignition switch on the lower column. Haveing said that, Ive never seen a switch go bad that let the vehicle start....most times its the acc. wire that melts- yours may be bad, may even just have slipped and need adjustment.

you thought the headlight switch was bad? If its the ignition box, prepare to stand on your head.

thanks for all the replies everyone.

i can check the iginition switch tonight. i would have thought that the headlights are an independant circuit, and have no connection to the ignition switch, as they *should* be operable when the car is not running, right?

any hidden fuses/relays/switches i should check? anyone out there with a wiring diagram that can check to see what else i should be tracing? i'll be picking up a manual this weekend, once i can convince the wife i need the other car!

thanks again for all the help guys....

There is a ground point that if loose will cause no end of screwy symptoms on an XJ. It is in the left rear of the interior. It is behind the plastic side panel approximately above where the retainer is for the spare tire. When loose, the ground is found by backfeeding through various circuits, so every time you do something, you get a different response. It has several wires with lugs that are held to the sheetmetal by a sheetmetal screw. I've solved problems for 6 different people that were having wierd problems by cleaning and tightening that connection. LOL

ground point behind the spare tire....cool. i will definitely check that tonight.

the problem does not seem to be dynamic, however. i suppose that is a good thing!

besides the fuse panel under the dash near where the dead pedal would be, are there any other fuse locations? i'm a toyota guy at heart, and i know in my toyota there is a fuse block in the engine bay with fuses for things like headlights, in addition to the ones in the drivers side kick panel. perhaps the XJ has more fuses that i just don't know about?

do relays go bad? could that be causing my problem? if so, is there a way to test a relay?

thanks again everyone!

Look on the engine side of the firewall, under the master cylinder. Sometimes they leak and the brakefluid eats the wiring. Start checking grounds, all of them.

RichP said:

Look on the engine side of the firewall, under the master cylinder. Sometimes they leak and the brakefluid eats the wiring. Start checking grounds, all of them.

Click to expand...

thats what is happening to mine. real pita.

hey guys,

spent some time yesterday checking/cleaning/tightening grounds, checking the wiring as it enters the firewall below the m/c, and looking for other loose connections. i had also changed the headlight switch.

still no luck.

i'm getting to the point where i need to take the car into an automotive electrical place for them to diagnose the problem. one of the guys i spoke with (at an electrical place) suggested that the problem wasn't a ground, relay, or switch issue. he suggested i check the source wire going from the battery, as perhaps it was the culprit. as i look at the engine bay, there are 2 wires that come off the + lead of the battery, and one of them connects to what appears to be another distribution block. before i start tearing into ALL of the wiring, removing looms, etc, can anyone help pinpoint what i should be doing more specifically?

thanks again for the help guys.....

check the fusable links in the starter relay near the battery.. these tend to work harden and break on older XJs.

A fusable link looks like a fat wire, green or orange in color, however it is actually thin wire with alot of insulation.

The insulation is rubbery, you can tug on the link and if the wire inside is bad, it will stretch.

I'm also thinking of something along the lines of a fusable link or a
broken wire of another sort. All of the "dead" items you mention are
things that WILL OPERATE with the ignition OFF. So I can't imagine
that the ignition switch is involved in any way.

Example: the hazard lights (which work with the ignition off), are dead...
but the turn signals (which only work with the ignition on) work fine.

So I'd definitely be looking at where those "switched" and "unswitched"
circuits are separated initially. Possibly a fusable link, possibly at the
underhood relay/fuse box, etc for a blown link or a corroded/broken
connection.

Unfortunately, (a) I'm no expert, and (b) my Jeep's a 2000, which is a
whole different beast, electrically.

Den

THANKS!

i guess i'm on the hunt for a fat green or orange wire near the battery. what both of you guys say seems to make the most sense. now its just a matter of finding which one is causing the problem.

i don't know why, but wiring is a mystery to me. i can do the mechanical stuff, but the electrical stuff gives me the creeps.

anyone know if the wiring diagrams for the 89 are the same as 88? Although I have an 89, i downloaded the diagram for the 88 on the internet.

thanks...

I would bet the wiring did not change here from 1987 to 1990. From 1991 on Chrysler made a bunch of changes.

I have a 1990 XJ and a 1990 FSM. I have used the 1990 FSM to troublshoot problems with both my 1987 XJs and have seen no differences.

http://www.naxja.org/forum/showthread.php?t=12294
that should get you going on the right track.
pm me if u need more help.
im bored and i have a 89 fsm in my hand

The instrument lights,and the parking lights are also wired into the chime module.The module,located in the lower left corner of the fuse panel,is what makes a buzzing sound when you leave the key in,or seatbelt not buckeled.
I have been told that the module is famous for "shorting out".When it shorts out it it will pop the fuse for the inst panel,and also cause the parking lights not to work.Why it works that way,GOK,but any who,I found out$130.00 later that the module can be removed with no consequences.
As far as no headlights,I would lean toward the headlight switch.
To pull the chime module,there is a release tab on the left and up against the
left kick pad on the drivers side.After pulling the module,check the inst/park lights,if ya got lights,that was your problem.

frsno jeeper said:

http://www.naxja.org/forum/showthread.php?t=12294

Click to expand...

This link - http://www.cataclysm.net/xj/ - doesn't work. Any others?

In general my '89 Laredo has fusable links that give me problems every year. It's a pain in the butt.

Thanks everyone for the info. I managed to fix the problem this morning. Turns out it was one of the fusible links at the starter relay. On my ’89, the green fusible link attaching to 3 red wires was shorted. Seems there are subtle differences in the wiring harness between the 88 and 89, and the 88 diagram shows the green fusible link going to only 2 wires: headlight switch and haz/stop fuse.

I went ahead and spliced in another 18 GA wire to replace the blown link, and it is now working. Is this an okay fix? Do I need to replace it with a correct fusible link?

Also, should I be worried that it did blow?

Thanks again everyone…..

No, yes, yes.

any ideas why it would suddenly blow? can it just be "old age"?

what is the amperage of the oem fusible link?

thanks.....

short to ground in the headlight harness?
some knucklehead spliced the headlight harness to run aux fog lights?
anything is possible.................. that being said, there is no "easy"
way to diagnose your prob., other than to open stuff up and look.
i might try the headlight switch first.
if you want, i can give you a list of the circuits that run off of the SAME FUSIBLE LINK.
its possible that your problem isnt even related to the headlights.....
i had a problem very similar(sp) to yours after i put my headliner in......... turns out that
i pinched the vanity mirror light wire during the install and it was on the same circuit
as alot of other crap.....


NOW is an awsome time to get a fire extingusher if you dont already have one.It would be a damned shame to lose your rig over the wrong fusible link!