[UncleBuck]

As a Jeep newbie (in this life: I have also owned CJ-2A and a pre-1954 Station Wagon) I need some assistance.

Rig: 1998 Grand Cherokee Laredo

Malfuntion: Dome, Courtesy and Cargo lights inoperative under any conditions.

Checked so far: Fuse 16 (in kick panel fuse block) - Checks OK (continuous with voltmeter, but I replaced it anyway)

Instrument Cluster lights, head- tail- and brake lights functional.

I bought this ZJ off eBay and, after spending 1.5 House Payments to get the tranny rebuilt it now runs pretty good, if you ignore the bearing/pinion noise from the rear.

However, I have to wear a little plastic Miner's Light on my head to do anything around it at night.

Any guidance available would be appreciated. I have a voltmeter and a big stack of fuses, but only the Owner's Manual and a really bad Haynes.

Someone in my local 4WD club mentioned a "Courtesy Light Relay", but he drives a TJ and I think this might be poor info.

Is there, in fact, a Courtesy Light Relay on a 1998 ZJ?

In the dark in Las Vegas,
UncleBuck

[mylt1]

check the door switches.

[UncleBuck]

1. Checked 4 door switches:

RFront: 12V
RRear: 12V
LRear: 12V
LFront (Driver's Door): 0 Volts

This confuses me even more, as the Door Buzzer (which sounds when the key is in the ignition in the OFF position and the Driver's Door is OPEN works just fine.

Any ideas? Any speculation?

[UncleBuck]

Does CHILTON'S have a decent electrical schematic for this sled? I hate to pay $25 plus shipping to find out that it's no better than my PITA Haynes manual (none on local parts house shelves), and I am REAL allergic to parting with $80 for a FSM.

[spuddybuddy]

PM'ed you instead

[UncleBuck]

Well, THAT was interesting.

Replaced Courtesy Light Relay and Fuse (again). Relay pulls in, Courtesy/Dome/Cargo, etc lights all come on.

BUT: they don't go OFF. Will probably make it tough to crank in about 5 hours.

I assume at this point that I have one bad Door Switch in the circuit, but I am open to suggestions...

I hate my Jeep...

[UncleBuck]

Replaced Driver's Side AJAR Switch. Switch function OK, per ohmeter and 12V to it.

No change. must remove Fuse to kill DOME/COURTESY lights.

Two speculations:

1. I don't find a LIFTGATE AJAR Switch. Is it, possibly, a mercury switch inside the LIFTGATE, or have I just missed it?

2. Could a LIFTGATE GLASS AJAR Switch be switching the circuit to ground?

3. Is there a COURTESY LIGHT SWITCH function in the HEADLIGHT SWITCH? (BTW, I have NO FOG, NO AUTO-DIM Headlamp Switch)?

Just changing out parts is making me feel like a real amateur. Luckily, so far they have been CHEAP parts.

[K1dS3ns4t10n]

I'm not familiar with ZJ's but I know my TJ has a courtesy light dimmer that rotates on the turn signal lever where the headlight controls are. If I rotate it all the way up the courtesy lights will be a max brightness and if I keep turning it will click into an always on position. Perhaps there is a similar control on your ZJ and its in the always on position.

[UncleBuck]

Since the dome/courtesy lights never worked properly, I only recently found out how to turn them ON. My ZJ has a 3 position rotary switch (OFF-PARK-ON) for the headlights. To the right of it is a sliding control potentiometer (slide pot), which controls the brightness of the instrument lights.

When the slide pot is slid completely UP, the dome/courtesy lights should come one...I just learned this yesterday from another ZJ owner.

The equivalent on your TJ would be to turn the dimmer control until it clicks.

Best price I can find on a decent used Headlight Switch for a 1998 ZJ is about
$50, with the Shipping, and, there are at least 3 different headlight switches for the 98 GC, depending upon accessories and trim level.

The Good New is: thanks to spuddybuddy's generosity in passing me an electrical drawing, I now have the pin-out data for the switch.

Wednesday I will pull my existing headlight switch out and ring it out with a DVM, checking to see if those two pins ever open, before I spend $50 for a switch.

So, your conclusion and mine are pretty similar.

If the switch is bad, of course, I could always just snip the wire that turns on the dome/courtesy lights...and save the $50.

Thanks for your input. Will keep you posted.