Brake Light Stumper - JeepForum.com
 
LinkBack Thread Tools
post #1 of 7 Old 04-19-2017, 05:36 PM Thread Starter
mocadedhed
Registered User
2001 XJ Cherokee 
 
Join Date: Apr 2017
Posts: 4
Brake Light Stumper

Hi - I have an 01 Jeep Cherokee 4.0 sport. Issue was that the license plate light had gone out. replaced several times and it worked for a while, then stopped working. I also noticed that my rear tail gate electric lock had stopped working. I pulled the rubber boot down and saw two wires had broken.

Since I couldn't get to the wire to reconnect I cut all the wires in the harness (now looking like a really bad idea) and pulled the wires through either end of the rubber boot that goes from the frame to the top of the lift gate figuring I'd just reconnect them all again with enough wire to make the connections, tuck them under the trim work and be done.

With the wires all just hanging and outside the boot I got everything connected back and working. License plate light, and rear door lock was working again etc. Great - everything repaired.... but when i disconnected all the wires, routed through the boot and everything works ... except the brake lights won't come on! Parking lights do, but nothing to the second filament - the brake lights.

1. Replaced the stoplight pedal switch
2. Checked parking light bulbs - they're fine
3. Checked fuses for parking lights and they're fine
4. Checked the rest of the fuses for the heck of it - all good.
4. Checked all the fuses in the engine bay - they're all good.
5. Removed the Uhaul Trailer plug I had installed years ago
6. Confirmed wires from connector plugs in rear of the jeep to the bulbs are good.

I'm stumped. Seems odd that the issue isn't related to the work I was doing ... but again, I'm stumped.

Is there an inline fuse somewhere that I may have blown? I guess it's possible that a wire would have gotten fried without the fuse having blown?

Thanks in advance for any help!

mocadedhed is offline  
Sponsored Links
Advertisement
 
post #2 of 7 Old 04-19-2017, 05:57 PM
CJ7-Tim
Real Jeeps have dents
 
CJ7-Tim's Avatar
2000 XJ Cherokee 
 
Join Date: Apr 2002
Location: out in the garage - Minneapolis
Posts: 25,604
Wondering some what makes you sure the brake light thing is not related to the tailgate wire harness work ? Plug and Play U-haul trailer lights, or hard wired ?

Replaced the brake light bulbs ? Checked the ground connections behind the spare tire with your volt/ohms multi-meter, and continuity of the brake light sockets ? Tested the fuses ?

Buy, borrow or rent something similar to this >> Automotive Cable Wire Tracker / Short & Open Circuit Finder and Tracer. The more inexpensive ones are about $40.

.

A recent Gallup public opinion poll shows the NRA, at 58% approval, has a higher approval rating than either Hillary Clinton or Barack Obama.

Progressive Liberalism: Bringing you new Healthcare ideas so wonderful, they have to include mandatory participation ...

Originally Posted by Ronald W. Reagan: Government is not the solution to our problems; Government is the problem.
CJ7-Tim is offline  
post #3 of 7 Old 04-19-2017, 06:16 PM Thread Starter
mocadedhed
Registered User
2001 XJ Cherokee 
 
Join Date: Apr 2017
Posts: 4
I did replace the brake light bulbs - Same result.
I did check the ground connections behind the spare tire - good and snug.
It was a hard-wired UHaul Trailer plug. Now removed. I'm back to stock there.

I haven't checked the brake light continuity ... I guess I was assuming that since the parking light was coming on (one of the filaments) that I was good there. I'll have to borrow a volt meter to measure output a the plug. Could it be that the system isn't providing enough juice to light the second filament when I depress the brake?

Neither Brake light is coming on now.

Right now I've disconnected all the wires that I had wired in from the harness. It's just hanging there with several wires hanging open ended. That's after I made triple sure that I had all the connections correct. I decided to undo all that work to remove it from the equation... maybe that wasn't the right approach?

I'm *not* sure the brake light thing isn't related to the harness work ... however, those two looms are split at the mini junction area behind the spare tire. I'm wondering if I've baked a wire somewhere along the body, but the fuse didn't blow. Seems unlikely. Have you seen that before?

I'll research the automotive cable wire tracker / short & open circuit finder and tracer. maybe that is the answer to finding where the break is.

Also, I forgot to mention in my original post - I'm an idiot. When I cut all the wires in the tailgate harness I failed to disconnect the battery. I can't find evidence of having caused a short and blown a fuse, but I'm sure it wasn't the best idea. But like I said - after I'd done that and reconnected all the wires everything worked including brake lights.

Last edited by mocadedhed; 04-19-2017 at 06:21 PM. Reason: Additional information
mocadedhed is offline  
 
post #4 of 7 Old 04-19-2017, 06:51 PM
CJ7-Tim
Real Jeeps have dents
 
CJ7-Tim's Avatar
2000 XJ Cherokee 
 
Join Date: Apr 2002
Location: out in the garage - Minneapolis
Posts: 25,604
Unplugging the tailgate wire harness is how I would eliminate it from the list of potential causes. Incorrect wiring during the repairs, or crossed wires causing a short circuit or open circuit is something to consider. Don't forget the third brake light in the tailgate.

The parking/tail lights and the brake lights are separate circuits. Poorly installed hard wired trailer lights can damage the wire harness, and for that matter so could un-installing them. Have you looked around for a stray ground wire that didn't get grounded ? All the fuses are in the fuse boxes, but a melted wire is a possibility.


Really the only way to answer the questions or rule in/rule out any of the possibilities is a volts/ohms multi-meter and some testing of the individual wires and circuits.

.

A recent Gallup public opinion poll shows the NRA, at 58% approval, has a higher approval rating than either Hillary Clinton or Barack Obama.

Progressive Liberalism: Bringing you new Healthcare ideas so wonderful, they have to include mandatory participation ...

Originally Posted by Ronald W. Reagan: Government is not the solution to our problems; Government is the problem.
CJ7-Tim is offline  
post #5 of 7 Old 04-19-2017, 07:19 PM Thread Starter
mocadedhed
Registered User
2001 XJ Cherokee 
 
Join Date: Apr 2017
Posts: 4
Good idea about disconnecting the wiring harness at the mini connector box area behind the spare. I'll try that tomorrow.

Do you think it's very likely that a burned wire happened without tripping the fuse?
I haven't gotten new fuses for the parking brakes because they look fine to me. not broken... but I can try that as well.

it just seems weird that both brake lights from both sides would have gone out if it was a single wire that had burned out.

I was thinking of bypassing the whole body with loose wire connection from the stoplight brake pedal switch to the exposed wires in the tail light housing to see if I could make them come on. Not sure of which wires to connect though in the bypass....
mocadedhed is offline  
post #6 of 7 Old 04-19-2017, 07:57 PM
CJ7-Tim
Real Jeeps have dents
 
CJ7-Tim's Avatar
2000 XJ Cherokee 
 
Join Date: Apr 2002
Location: out in the garage - Minneapolis
Posts: 25,604
A volts/ohms multi-meter is the Droid you are looking for.

.

A recent Gallup public opinion poll shows the NRA, at 58% approval, has a higher approval rating than either Hillary Clinton or Barack Obama.

Progressive Liberalism: Bringing you new Healthcare ideas so wonderful, they have to include mandatory participation ...

Originally Posted by Ronald W. Reagan: Government is not the solution to our problems; Government is the problem.
CJ7-Tim is offline  
post #7 of 7 Old 04-23-2017, 09:03 AM Thread Starter
mocadedhed
Registered User
2001 XJ Cherokee 
 
Join Date: Apr 2017
Posts: 4
Thanks for the replies and suggestions. Turns out that while I said that I'd checked all the fuses, which I did - apparently I didn't check close enough. #23 15Amp Fuse under the hood had blown. All back together and working again.


Have a good one.
mocadedhed is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome