How to fix a stubborn brakelight?
June 3, 2007 10:32 AM Subscribe
Auto Mechanic Filter: I've got a bum brake light in my 2000 Jeep Grand Cherokee. I don't really have to take it in, do I? (And yes, I've already tried a fresh bulb :)
Help! My tail light works fine when I turn my lights on, however when I hit the brakes, the bulb goes dead. When my lights are off, and I hit the brakes, the bulb works fine. I've replaced the bulb, but I still get the same problem. The other tail light has no problems.
It looks like the bulb has two filaments, I'm assuming one for tail light one for brake light, they seem to be working seperately, but not together! What's up with that?!
(This is a 6cyl 2000 Jeep Grand Cherokee btw)
Help! My tail light works fine when I turn my lights on, however when I hit the brakes, the bulb goes dead. When my lights are off, and I hit the brakes, the bulb works fine. I've replaced the bulb, but I still get the same problem. The other tail light has no problems.
It looks like the bulb has two filaments, I'm assuming one for tail light one for brake light, they seem to be working seperately, but not together! What's up with that?!
(This is a 6cyl 2000 Jeep Grand Cherokee btw)
Cops will give you trouble, but they'd probably just give you a warning. I've never heard of anyone getting their car towed for a malfunctioning brake light.
I'd take it in.
posted by BeaverTerror at 11:00 AM on June 3, 2007
I'd take it in.
posted by BeaverTerror at 11:00 AM on June 3, 2007
Maybe dumb questions, but: are you sure you've got the right bulb, and that you've got it installed correctly, and that neither filament is burnt out? When you bought the replacement bulb, there were probably two in the package. Have you tried the other one?
posted by box at 11:08 AM on June 3, 2007
posted by box at 11:08 AM on June 3, 2007
Response by poster: box, yes I tried both bulbs in the package, and both the tail light and brake light work in the same bulb, just not at the same time like they're supposed to...
steven, beaver, I am planning on taking it in if it turns out there is no other fix...i have no intention of driving without a brake light
posted by 777 at 11:12 AM on June 3, 2007
steven, beaver, I am planning on taking it in if it turns out there is no other fix...i have no intention of driving without a brake light
posted by 777 at 11:12 AM on June 3, 2007
I can't find a wiring diagram for a 2000 Jeep Grand Cherokee, but here's a 1998 diagram.
If that accurately represents the wiring in your Jeep, my guess would be that you have a bad lamp outage module. The fact that the lights work independently and the problem is only on one side indicates to me that it's not a wiring problem, but a bad component. Check your manual. It might be something you can test yourself. Check your fuses, too. Weird things can happen when one goes out.
If you take it in and they tell you it'll cost $500 to track down a wiring problem, I'd say they're full of it. Judging by what you told me, the first test they should perform is replacing the appropriate relay with a known good one to see if it fixes the problem. Labor should be less than an hour in that case. Don't let them go trying to track down a wiring problem. There almost certainly isn't one.
Also, I'm not a car mechanic.
posted by dsword at 11:17 AM on June 3, 2007
If that accurately represents the wiring in your Jeep, my guess would be that you have a bad lamp outage module. The fact that the lights work independently and the problem is only on one side indicates to me that it's not a wiring problem, but a bad component. Check your manual. It might be something you can test yourself. Check your fuses, too. Weird things can happen when one goes out.
If you take it in and they tell you it'll cost $500 to track down a wiring problem, I'd say they're full of it. Judging by what you told me, the first test they should perform is replacing the appropriate relay with a known good one to see if it fixes the problem. Labor should be less than an hour in that case. Don't let them go trying to track down a wiring problem. There almost certainly isn't one.
Also, I'm not a car mechanic.
posted by dsword at 11:17 AM on June 3, 2007
Check the simple things first. If you look carefully at the bulb, it has two prongs sticking out opposite sides of the brass base. These prongs are not aligned--one is higher than the other. You can insert the bulb two different ways, 180 degrees apart, but only one way is the correct way to twist and lock those prongs into the receptacle and make the correct contact. Poor design, basically. Try inserting the bulb 180 degrees (switching three o'clock for nine o'clock, if that makes sense). It is also possible that you have a fuse burnt out. Fuses are often different for separate sides of the car so you don't lose, say, both headlights at once.
posted by weapons-grade pandemonium at 11:37 AM on June 3, 2007
posted by weapons-grade pandemonium at 11:37 AM on June 3, 2007
Oh, and if you or someone else has previously tried to insert the bulb incorrectly, a bent receptacle may be the problem.
posted by weapons-grade pandemonium at 11:39 AM on June 3, 2007
posted by weapons-grade pandemonium at 11:39 AM on June 3, 2007
Response by poster: thanks for all the input so far...how simple is a fuse replacement? is it something i can do with a little research...thanks in advance
posted by 777 at 1:46 PM on June 3, 2007
posted by 777 at 1:46 PM on June 3, 2007
Changing a fuse is dead simple, although you may want to get a fuse puller from the auto parts store to make it easier.
Just pull any fuses that might be related to the lights and inspect them to make sure they're still good. It'll be plainly obvious when you look at them what you're looking for.
posted by wierdo at 5:42 PM on June 3, 2007
Just pull any fuses that might be related to the lights and inspect them to make sure they're still good. It'll be plainly obvious when you look at them what you're looking for.
posted by wierdo at 5:42 PM on June 3, 2007
Best answer: You have a ground problem. There should be three wires running out of the socket for the bulb to the body of your Jeep. One is for taillight, one for brake light and one for the ground. (Usually a black wire) either at the socket or where the other end of the wire connects to the body is not making a good contact. At the socket it could be broke. My bet is on the connection to the body. If you can find it, take it apart, clean it up and put it back together. Should work after that. Good luck.
posted by GeneticFreek at 10:45 PM on June 3, 2007
posted by GeneticFreek at 10:45 PM on June 3, 2007
Best answer: thanks for all the great advice, after a little more online research i found the following article
looks like many others have had this same problem, and sure enough, it was a 5 min fix involving the ground contact
posted by 777 at 8:27 PM on June 4, 2007
looks like many others have had this same problem, and sure enough, it was a 5 min fix involving the ground contact
posted by 777 at 8:27 PM on June 4, 2007
Well, I'll take my foot out my mouth. It was a wiring problem. I don't really see why the socket itself doesn't ground to the body, though. Oh well.
I apologize for the miserable advice. I'm glad you didn't take it and buy a new part, and I hope I didn't waste much of your time!
posted by dsword at 9:48 PM on June 5, 2007
I apologize for the miserable advice. I'm glad you didn't take it and buy a new part, and I hope I didn't waste much of your time!
posted by dsword at 9:48 PM on June 5, 2007
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posted by Steven C. Den Beste at 10:58 AM on June 3, 2007