Well that's how the passengers see it. Drivers, of course, are of the
opposite opinion.

<sorry!>

Step by step?

A) Swap the headlamp bulbs and see if the problem travels with the
bulb.   This would also be a good time to upgrade to a new set of
Wagner Tru-View lamps, you will be amazed how much better they are
than stock plus they don't overload the stock wiring and switch!

B) If "A" didn't do the trick, take a Digital Multimeter (voltmeter)
and check the voltage at each headlight connector.   Be sure to turn
on the lights and don't forget to switch them from "DIM" to "BRIGHT"
and check both circuits.   Should be almost the same as checking
between the battery posts, without the engine running around 12.3 to
12.6 volts.   If they check good voltage, check the resistance of the
Ground Circuit of the headllight connector using the "Ohm meter"
feature of the Multimeter, it should be virtually "0.00".   Sometimes
each headlamp has it's own ground circuit, you may have loosened one
during your mechanical adventure so trace the ground wires to see what
you have.

Good luck, Bruce

Assuming the lamp itself is good it appears that you have a circuit
grounding problem.

You will need to get in there and manually clean (and coat with dielectric
grease) the ground connectors and connections.  Perhaps another Jeeper can
give a specific locations to check, I'll just say take apart and clean every
connection you can find.

FWIW.... I had a '68 Rambler American with the same problem which occurred
at some very inopportune time so I temporarily added an additional ground to
the circuit by tinning both ends of a section of 14g house wiring and using
it as a jumper from the ground side of the dim headlight to a bolt on the
grill.  I drove that Rambler for a number of years before giving it to my
baby sister who drove it until 1986...... with that temporary fix still
doing its job! (Not that I recommend you do this bit of hillbilly
re-engineering)

The ground tags for the headlights are on the back of the grill.  I
would be thinking one of these wires got damaged or is loose.

Or a loose plug on the back of the light...

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos:  Non members can still view!
Jan/06 http://www.imagestation.com/album/pictures.html?id=2115147590
(More Off Road album links at bottom of the view page)

 Check for a bad ground on the dim headlight.

Almost CERTAINLY a bad connection (it could be ground, ...  or it could be
power source i.e. corroded plug contacts etc.).

There's no bulbs to swap ... per se .... except the sealed units themselves
....... but sealed units are (generally speaking) either working, ... or not
working ..... i.e. with proper connections, the light is either on or off. A
dim light indicates bad current flow .......

My guess would be bad plug connection

Sounds like a bad ground on one side unless the ground wire inside the
light broke loose.

I think the coincidence is that the headlight broke while it was on the
bench.