t_mac

Hello, I need some help with troubleshooting my 1998 XJ 4.0L sport rear lighting issue.

A while back my headlights stopped working except the highbeams - so I checked the fuses, replaced the lamps, replaced the daytime running module (I'm in Canada), changed the headlamp pull switch on the dash, took apart the steering column and changed the high beam/turn signal switch -- eventually I got my headlights to work. Now my taillights and brake lights don't work at all... the parts I replaced for the headlights were all used parts from a local auto wrecker, could there be an issue with one of those switches I replaced? if so, which one should I check? Or could I have shorted something out while changing them? I was doing the repairs on the side of the road during the harsh winter here in Canada so I may have not disconnected the battery (don't remember...). I don't have a factory repair manual, and I can't find the diagrams for the wiring harnesses to troubleshoot if there is a ground fault, etc. Any advice?

I've done similar repairs on my 1992 YJ I used to own, but I'm hardly an expert... I needed the step-by-step guide from my electrical service manual to follow and find the problem. Any help would be greatly appreciated as I can't afford a mechanic to help me get it running again.

BlueRidgeMark

Welcome!

First thing, check your grounds. See my sig, #1, for a link to the ground locations.

t_mac

Hey thaks for the link to those grounds, the pictures are very helpful. I disconnected and cleaned each contact point for the 4 main engine bay grounds with a wire brush and some sandpaper. I also checked the contuinity with an Ohmmeter. They all had zero resistance except the G102 grounds - one showed resistance (see attached photo) but since it runs through the OBD DLC I'm not sure that it means anything.

Nothing changed on the brkae lights after cleaning those ground connections up.

Here's what I have done so far:

- I re-checked fuse #7 and fuse #23 for the rear parking lights in the interior passenger side fuse panel. The fuses are both good
- I removed the new bulbs I had put into the tail light sockets and tested with a volt meter for any power - no power to either socket. I removed the insulation to the wires behind the sockets and tested for voltage - no voltage. I tested the bulbs with an ohmmeter and the bulbs are good.
- I removed the harness for the Brake Lamp Switch (see diagram 8W- 10 - 33 and attached photos) and tested for voltage in the harness slot #1 had 13.35 volts - # 2 had 0.01 v - #3 had 0.00v - #4 had -0.02v - #5 had 0.00v - #6 had 13.05 v ** when I re-attahced the wire harness my driver side (left) brake light started working... still no reverse lights or passenger side brake lights or reverse lights.

At this point my turn signals all work ( front & back) my driver side (left) brake light works, and the center mounted brake light work -- but not my passenger side (right) brake lights or reverse lights.

I'm stumped... any advice on what I should try next?

t_mac

t_mac

these are two of the switches I replaced to get my headlights to work. I assumed that maybe the tail lights issue was related as it only happened after I was replacing my headlight switch.... Any thoughts? or how can I test that this replacement switch is good? I took it out of a jeep at the auto wrecker

t_mac

he

here's a better view of that wiring harness for the brake lamp switch. One of the wires is damaged (slot #6) and was like that when I removed it. This slot in the harness has 13 volts running to it.

Should I replace this switch and harness? Without an electrical service manual I am having a hard time troubleshooting these individual components... does anyone have a section of the maunal they can share with this particular component?

t_mac

I just found that there are 2 grounds inside the rear drivers side panel (see photo) but is there another ground for the passenger side brake light?

I thought the taillights were working when I played with the brake switch, but they still aren’t working — just the drivers side brake light and centre mounted light (with brake switch button released)

t_mac

When I look at this interior cluster (see photo)

I am not sure what I should be checking.... there is a rusty opening under the rear drivers fender (I can see light coming through) so potentially some water damage in these wires?

What should I check?

BlueRidgeMark

Looks like you've got some trailer wiring in there. That and the ingress of water is probably the source of your problem.

Look for corroded connections.

t_mac

Thanks! I agree having water coming in is a problem. I found the trailer wiring among this cluster and everything looks good (I don't know how to test the trailer wiring) - no broken wires, connectors are all dirty on the outside but not corroded. I just keep researching and searching other threads for missing info or learning stuff as i go...

I took apart the passenger rear panel as well - the same problem with water access to these wires through a hole on the panel. ***On the passenger side, the connection (C321) looks corroded inside (see photo) and water must've gotten inside... *** I tested with a voltmeter and I am not getting any power to this harness with the lights on. I found a wiring diagram from a 1997 xj (see photo it's a different diagram than the other one I posted earlier that I found online.) -- am I reading this correctly? It looks to me like I should have power at all times to this harness C321 from the dark green wire and then the stop lamp switch closes that circuit? There are 2 harnesses there, one that runs up the frame possibly to the CHMSL? but I can't see where it goes unless I also remove that hatch door panel.

I'm also searching for this G303 ground as I heard it may be under the passenger seat? Do I have to remove the passenger seat for access?

I looked for this C321 wiring connector on Rock Auto.com and Moriss 4x4 but couldn't find it. Does anyone know what the part would be called? I'll try the local auto wrecker tomorrow... but replacing with used parts has me wondering if I'm creating problems, adding to my uncertainty or it's just a coincidence... I'm broke so it's a problem. If I can't get this jeep running I may have to sell it, but I love it problems and all. I used to have a 1991 YJ for 10 years and kept it running but it was in rough shape when I sold it (I'm obviously not a mechanic) -- but I always regret selling it, so I bought this XJ when it came up for sale... but it's got some issues too lol but I found parts are easier to find for it


C321?

top view of c321



. Once I figure this wiring out I'll be tackling the next big job...

t_mac

As far as I can tell I only have 1 ground to locate and check... G303 -- There seems to b conflicting information on this location. Does anyone know where it would be on a 1998 XJ sport?


Once I check this ground and change those water damaged C321 connectors -- if my taillights/brake lights still don't work what should I try next?