Brake Light Problem on 2000 JGC

The left brake light has a broken filiment. Let me restate that, the left brake light is getting its ground throught the left side running light. When the left side running lightis ON, there is no ground potential, and the brake light stops working.

Replace the offending bulb.

Having said that, the ground for the lights in Jeeps is known to not be very good, but your 2000 should not have trouble yet. The fix is to completely remove the light assembly - you may as well take them both off and do the same thing - and identify the screw that physically grounds the asembly to the fender, and clean the contact points with very fine sand paper or steel wool. A good strategy would be to take a pigtail lead from the ground screw to another point inside the fender, this would require drilling another hole that would not be visible from the outside. I would use a star washer that could punch through the paint ...

Jeff, thanks for the info, and I will work on the ground situation.

But, as I said in my original post, I have put a new bulb in the left brake light, so I doubt it is a bad one.

--James--

The brake light and signal ground through the fizture bolts, the running lights ground through the wiring harness.

You have changed all the rears out, but you still have tow up front connected to the brake circuit, the front signals.

Do the signals work? They use the same bulb element as the brake lights.

If not, then I would next look at the front bulb for a loose glass part or filament short....

If it is ok, then I would be looking at any trailer hitch plugs.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

James wrote:

That is not a safe assumption, I have taken out a bad bulb and put in another bad bulb on many occasions. The trick is to test the bulb before you put the lens cover back on.

Take the lens cover off of BOTH sides, then take a known good bulb and put it in the offending socket. If the problem follows the bulb, then the socket is needing attention, if the good bulb works on both sockets, then the offending bulb is bad.

There are two filiments inside the bulb, one for the running lights and another for the brake lights. Use a multi meter, or multiple bulbs and sockets, to test the integrity of a bulb. If a bulb works in one socket but not another, then the offending socket is the problem, if the bulb fails in more than one socket, then the bulb itself is bad. The common point on both bulbs and sockets is the ground, which is the case of the bulb and the outside of the socket.

Buy a new back light assembly for the side that is giving problems for 150 dollars and your problem is solved or better yet try the junk yard.....It is the bulb holders piece that has gotten hot and melted and preventing good contact.....you cant and I repeat cant buy the bulb holder assembly by itself even though it has screws to remove just that part that is causing the trouble.....I was denied warranty due to it being apart of a cosmetic part......trust me, I know, I have battled this problem.....good luck...quick way to test is switch assemblies from the good side and you will see problem solved......

Heck yeah. Doesn't seem like it would be too difficult to just take the internals of a trailer tailight and install the bulb holder from that into the GC taillight assembly.

You 'can' buy replacement pigtails that you can put in. I used them in all my light fixtures when I rebuilt my CJ7. They are inexpensive unfortunately, I would have preferred higher quality parts, but 5 years later they all are still working.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Matt Macchiarolo wrote: