On 2000 Grand Cherokee Laredo... When the head/tail lights are ON, only the left tail/running light actually lights up. But when I apply the break, the same left tail light goes out completely. At the same time, the right brake light (previously not lit at all) comes on.

So I've got a tail/running light but no brake light on the left, and a brake light but no tail/running light on the right.

Does anyone know why this would be?? All bulbs appear to be fine.

Thanks.

 

When strange things like this happen with vehicle lights, more often than not, the problem is due to a poor electrical return path(s). This can be due to corrosion where a wire/chassis connection is made.

I suspect both sets of rear lights share an electrical return path – take a close look at the common wiring between the lights. Check the integrity of all wiring connections, especially the chassis/return wiring.

 

I am having the same problem with my 2000 Jeep Grand Cherokee.

 

remove both your rear tail lights and remove all bulbs, clean corrosion out of bulb sockets and stuff em full of di electric grease. That did the trick for me!

 

Has anyone had any luck with this issue of the head lights being on but when applying brakes left taillight goes out?

 

I've been looking around for a fix for my Cherokee Classic tail light and came across this. Everybody on the forum raved about it...

"I tried this suggestion from a Jeff in Fort Meyers Florida also and it worked for me.
"This is the corrective method for your brake lights not working when your headlights are on(2000 Jeep Cherokee Larado).

1) The cause of the problem is heat from the bulb.

2) Remove the light assembly as if you were going to change a bulb.

3) Turn the socket and remove it from the taillight assembly and set it aside(check to be sure your bulb is not burnt out).

4) Look at the opening, you will see 3 flat chrome colored contacts on the assembly.

5) Notice the one by it self at the top of the opening, that is the “ground”.

6) If you look closely you will notice the plastic around the ground contact has shrunk a little bit, this caused the contact to pull away from the socket, causing the problem.

7) With a small flat head screwdriver, VERY GENTLY pry up the contact so it stays slightly upward by itself.

8) Re-insert the bulb assembly back into the housing and press your brake petal with your lights on.

9) You should be in good to go!

10) Tools: Phillips head screwdriver and a small flat head screwdriver.

11) Time : 5 minutes per light "

This suggestion really works. Saved me a lot of money rather than taking to a shop."

 

My 99 starting doing this. When I pulled the bulbs, I found that the sockets were melted (probably because of bad grounding). Got new
scokets from Oreillys. I think they about $2 each.