tazman wrigglesworth

I have a 2000 Sport with new 4.0, factory driveline and headlight problems. I have driver side low beam, and high beam on both sides. I just don't have low beams on passenger side. I have aftermarket projector lights with Silverstar bulbs. Bulbs are good (even plugged in old sealed beams with same results). Checked front loom behind header panel and have no power to low beam side (purple wire w. red stripe). I followed this wire to the main connection by the airbox. No power at all to connection. What is the best way to check the remainder of the problem - continue continuity check on wires from plug to fusebox, check/replace headlight switch or check/replace dimmer switch on steering column? Looked all over forum and don't have a clear answer. Any help would be good. Local cops like to stop guys with lights out.

NH_Jeep_XJ

The XJ does use a separate fuse for each headlight's high AND low beams (4 fuses) And share the same power source which is split between left and right headlights. Both Low Beam and High Beam.

The good news is that if you only have low beam power to one side, then the problem side's fuse is likely blown.

Fuses 4 and 5 are your low beam fuses.
So it's apparently not the switch. Or else you'd have no headlights at all.


Under the dashboard, In your passenger side footwell is your fuse box.

Check fuse #5, which starting at the upper left fuse counting down is in position number 5 down from the top, to see if it is good/bad.
Check number 4 as well for comparison.

If the fuse is blown, it is likely a short which occurred somewhere in the engine compartment between the fusebox and the headlight itself.

This is where you'd check for continuity, (disconnect the negative lead to your battery first) on the problem headlight's circuit. The Violet/Red wire back to it's fuse.Checking both sides.

Also check the condition of wires for potential problems like chaffing that could lead to water getting in for example and causing a short circuit.

Good Luck.

tazman wrigglesworth

Checked and replaced all fuses to high and low beam slots just in case fuse was bad. Still no power. Someone told me the switch and dimmer have separate "switches" in them that can wear and add gremlins to the lighting. I don't know, I figured if I have lights - low and high - then the switches must be working. As far as the continuity check, in which I am assuming you are using a powered continuity probe, do you check for it by probing the socket to the headlight (in this case, the lone plug on the three plug socket) and ground it to the chassis? Or do you check from the fuse panel, in this case the number 4 fuse for low beam passenger side? Any guidance is welcome.

NH_Jeep_XJ

A BASIC VOLTMETER is $17. at radio shack.

The continuity/ safe approach would be to pull the negative lead from the battery, pull the fuse number 4, reinsert the fuse with a jumper wire and with one probe on the jumper wire and the other on the headlight connector, test the continuity between the fuse and the low beam pin/connector on your headlight.

This would merely prove that we have a functioning circuit OR an open circuit from the fuse since both low beam headlights share the same power source from the headlight/dimmer switch.

The other and more simple way would be with the XJ in normal operating mode, ie battery connected. With your headlights off, wiggle/pull the headlight connector connector out enough to insert a probe into the headlight leads. The verticle leads are your high and low beams, the horizontal is your common (ground).

The Red lead would go to either of the verticle connector, and the black lead would go to the horizontal connector.

Set the meter to DC V 20. For 20 Volts range. Cars operate at 13.5-14. Volts. when running with the alternator turning. Your readings will make more sense.

Turn on the headlights and check the voltages.

You could check both sides/leads, the high beam noting the voltage reading , followed by the low beam side which most likely is at or near zero.

The good news is that we are pretty certain that you aren't getting voltage to the bad headlight and you could have brighter headlights for your XJ soon !!!


I'd look to upgrade the harness and headlights with something that carries more power to the headlights.

The Jeeps Headlights are probably one of the features of the XJ that really reveal it's 1970's heritage.

I haven't upgraded my harness yet, but I have replaced the sealed beam units with H4 Hellas and 80/100 bulbs which are technically for offroad use only. Since it's a Jeep and it runs off road sometimes....I leave them in all of the time !

I have a couple of other vehicles, one of which has HID's and it's hard to even drive the Jeep at night now.
I see HID's in the Jeeps future...

MickDime

I had a similar problem but my driver side high beam wouldnt work..checked the fuses, lights..did the whole bit.

Ended up being the wiring harness (that leads to both headlights) under the hood behind the driver side light.

wiggle that around see if its a lose wire..a bunch of mine happened to be lose

Hope that helps