Hello All:
I am on this forum alot but am not a very frequent poster,also I am usually reading the Cherokee tech as that is my DD. However I have a question about my wife's car that has stumped me. The vehicle is a 2003 GC, 4.0L auto 4x4 Laredo. About three weeks ago the Left Rear brake and running light abruptly quit working. SO I put a new bulb in assuming that was the problem. Now the brake light DOES work but the running light does not. Swapped in another new bulb just to be sure,same issue, ALL other lights work correctly,the right side functions fine, brake lights all work just no running light on the left. SO I bought a new socket from the dealer, thought that must be it. Wrong:-). Put that in today same issue no change. So im a bit stumped here any ideas? I am not as familiar with the GC's as my Cherokee, I did a search but found nothing. I apologize in advance if this has been covered, just looking for a nudge in the right direction. Also in advance love this site and all the people who take time to help others on here, I have learned a ton just by reading/watching! Thanks!

 

Nothing to check? No ideas?

 

What kind of bulb did you get?

 

Not sure have to check the ones that auto zone had listed. I did make sure they had two different filaments and appeared visually the same as the ones that came out.

 

Check a PM I sent.

 

If you do have a solution please post as this will help others research it in the future

 

But ya, sounds like a bulb issue, try this, take the bulb from the other side and see if it works in the malfuctioning side

 

Update:
Waiting for the the vehicle to get home tonight and will see what I can get. I will swap the bulb, ET Jeep I cleaned the connector in the back to no avail. I have a Multi meter(digital) but don't really know much about using it: what should I look for( Im guessing infinite resistance?) in order to check for bad ground or corrosion?

 

You are correct of course, I should have just posted. What was I thinking? I didn't have any solution, just a couple of tips. As a newbie here, I wanted to check the PM system and see how it worked. POST,POST,POST

 

Well, last night was power outage night. Twice I tried posting this and twice the power went out in the middle of posting. We have been getting hit with daily storms, Texas, for almost a week now. Friday a storm came thru with flat line winds 60-70 MPH. It toppled some trees, snapped the tops off about a dozen and blew some panels off the barn. Between downed trees, barn repair and wild hogs, they love this weather, I sure will be busy. OT, any ways,
　
First, try changing the bulb from the good side and see if it works on the left side. If it does not work, try the following: with a helper looking at the light, turn on the running lights, brake lights off, and use your turn signal lever left neutral right, move your tilt steering up and down and see if it lights or even flickers. . Some of these wires feed thru the multi function switch on the steering column. If you see even a flicker the problem is there. If that does not work, trace the wiring from the bulb to the power source and wiggle the wiring harness as you go. It may be a loose connection. As I said this is easier said than done.

If all this fails you will have to power check the wire from bulb to power source. To do this, first determine which wire feeds the running light. Unless you know which is the running light power wire, you can find this wire by working with the right side, good side. Turn on the running lights, brake lights off, set your meter to read DC Voltage set at 20V. Now look at the bulb connector to see if you can touch the wire contact with the bulb in and turned on. Touch the red test lead to the wire contact and the black lead to a good ground on the vehicle. If there is power you will read battery voltage around 12 volts. The wire with power is the one you are looking for. You will find a similar wire on the left bulb connector. If the wire contact is not accessible, take a pin and stick it into the center of the wire and touch your red lead to the pin, black to ground.

Once you find which is the power wire for the running light, you can trace it back to the power source. Use the pin to look for voltage. If you get to a point where there is no power and then there is power, the problem is between the two points. You can put some sealant on the pin hole to seal it. All this testing has to be done with the running lights on so care is required.

The problem is not the ground as your brake light works. They share a common ground. It is not a short as the right side works and you are not blowing any fuses. I believe you are not getting power to the running light wire. The diagram I am looking at is not for your year model but it shows the wire colors as Black=ground, Pink/white and Light Blue. One of the last two is the running light wire. Colors on your vehicle may be different.

I hope all this makes sense. Good luck with the troubleshooting.
　

 

Thanks for all the info, I will see what I can make happen tonight, here in the upstate of SC we have been flooding a bit for the last few days, and as such progress has been slow. However I did get bulbs swapped, no change, also cleaned the connector with electrical contact cleaner just for kicks. I will try the switch trick, if nothing then I suppose I will see what I can find with the DMM. I will update with findings,thanks again!