So replaced all my rear light bulbs with leds and noticed that when running lights are on the brake lights don't get any brighter when they are pressed?
replaced brake light switch and cleaned all the connections and disconnected the trailer adapter from harness. Have done cruiser54's ground fixes,still stumped.....

 

the brake/running light bulbs take 2057 bulbs

Tail Light Bulb Size: 2057
Stop Light Bulb Size: 2057

one bulb with 2 filaments and can only go in one way twist, disconnecting the trailer harness might have something to do with maybe lost a ground ?

marc

 

done that after noticing the light output difference. might just have to go back with oem stylebulbs. also remembered when you said i may have lost the ground, i can take off the ground wire from the chasis behind the rear drivers panel and the lights still work. im not sure if it has anything to do with that or not.

 

i would take the tail lights lose and have the brake pressed i use a broom stick to test this by myself wedge on the pedal and seat then wiggle the wiring while you sit behind it its so easy to have a lousy connection and hard to spot after replacing bulbs

marc

 

yea had my wife, then my 3 yr old daughter lol hit the brakes with the running lights on AND off. with the running lights off they work great.....on can barely tell im applying the brakes. i have all but jump roped with the wires lol. might just be really crappy leds. amazon special(get what ya pay for). gonna try with oems back in and see what i get. who knows might have sent me some 1156s or something instead of the 2057 equivilent leds. thanks for the help and ill keep ya posted if it changes.

 

yes compare the bulbs connections with the ones you had with the new ones, should both have two filament that might be your issue.

marc

edit: welcome to the forum btw

 

the 1156 looks like it has only 1 filament and can go in both ways the bionet pins are even, on a double filament bulb they are oneven and the bulb can only go in one way.

 

sorry run outside to look at the bulbs. they are 1156s. amazon shows i ordered 2057s so i guess ill be pullin em out and sending them back for exchange. always the most obvious huh. its worse when i do this for a living (diesel equip) and the times ive gotten wrong parts from the parts house. once again thanks ladykenai!!!! and thanks for the welcome have always used the forums for help, never signed in. another smack on the forehead on my partLOL

 

thats always a gamble if the clerk was sleeping or not ok glad you got it sorted out

marc

 

you dont have to send it back you can still use the bulbs for other sockets..

High and Low Beam Headlamp Light Bulb Size: H6054 or H6054 HID Kit
Parking Light Bulb Size: 2057A
Front Turn Signal Light Bulb Size: 2057A
Rear Turn Signal Light Bulb Size: 1156
Tail Light Bulb Size: 2057
Stop Light Bulb Size: 2057
High Mount Stop Light Bulb Size: 922
License Plate Light Bulb Size: 67
License Plate Light Bulb Size: 168
Back Up Light Bulb Size: 1156
Front Side Marker Light Bulb Size: 194
Rear Side Marker Light Bulb Size: 2057
Ash Tray Light Bulb Size: 1891
Glove Box Light Bulb Size: 194
Map Light Bulb Size: 912 or 561 or 906
Step/Courtesy Light Bulb Size: 906 or 168 or 53 or 561 or 74
Trunk/Cargo Area Light Bulb Size: 561
Under Hood Light Bulb Size: 105
Instrument-General Light Bulb Size: PC194 or 37 or 53 or 658 or 74
Hi-Beam Indicator Light Bulb Size: PC194
Automatic Transmission Indicator Light Bulb Size: 658
Directional Signal Indicator Light Bulb Size: PC194

marc

this list if for a 94 xj but i dont think there is much difference on a 88 xj

 

Some LED bulbs are very dull and produce a poor light output because of the low Lumen number, or you may need a resistor for the bulb like this one https://www.carid.com/lumen/led-load...-dcdr50w6.html