I noticed the other day that when I hit my brakes the brake lights are not as bright.
so I checked the bulbs and the housing and they were clean .
I also checked the ground by running another ground from the body but no change I also checked all the wire connections.
and also they kind of fade on when they come on.
the turn signal lights are bright but not the brake lights
they use the same bulbs.
I tried running a new positive wire to the switch but no change.
MAYBEE THE TURN SWITCH IS BAD?

 

The brake lights or the turn signal lights? If it's the brake lights as stated, why are you messing with the turn signal switch????

When you say you checked the bulbs and "housing", what exactly do you mean? The plastic housing?

And how did you check the grounds? Did you take them apart?

Have you done any checking with a multimeter? If so, what have you done, and what results did you see?

Did you check the sockets? How about the brake switch?

 

Had same issue same year. I upgraded my brake light switch not to see if it would make lights brighter but to get rid of the poor design in the process light got way brighter. Might wanna check input and out put voltage at switch it self. If you have this bracket above your factory switch just buy a universal switch install it in hole that aligns with brake pedal . Cut factory plug down middle and push each pc on new switch spades.

 

I checked the bulbs for corrosion and the sockets and the plastic housing for dirt that might be impeding the light from shining thru and all was clean .
I tested and cleaned the grounds and used a jumper wire and a meter and all were ok.
I checked battery voltage at the battery to get a base line and when I check voltage at the switch it is the same going in and coming out of the switch and the voltage is the same at the brake light sockets.
the only drop I see is in AMPS to the brake lights so I ran a temporary wire from the batt to the switch and still the same thing (DIM BRAKE LIGHTS).
BUT the turn lights are bright.
when I disconnect the connector on either side the light is bright when the brake light comes on but when I plug in the other side it gets dim.


The bulb layout on a wagoneer is different from a Cherokee
a wagoneer has two 1157 bulbs and two 1156 per side.
two of the bulbs are for the brake lights/running lights/turn
and the other is for running light and reverse.
Below is a pic of a Wagoneer tail light (not mine its of the internet)
and the bottom pic is a Cherokee.

 

I'll try that too.......


Thanks.

 

Okay! Sounds like you are doing all the right things. Help me get clear on what you are saying here:


This is the brake switch, correct?

If so, sounds like freedgr is on the right track.

Here's a tidbit that not everybody knows: When there is no load on a circuit, a voltage reading may look just fine, but when load is applied, the voltage may drop. This is due to resistance in the circuit. This is why a test light will sometimes show a problem that a voltmeter misses. The meter has a high input resistance, so it does not load the circuit. The test light applies a load (which is why it can fry modern vehicle electronics, so don't use it on just any wire on newer vehicles!), so it will show that kind of problem.

 

Subbed. This is good info. I can't wait to see the resolution.

My wires to that whole rear taillight area have been cut by the PO, so I'm soaking up related knowledge.

 

FIXED THE PROBLEM!
I removed the old incandescent bulbs and put in
high lumen LED bulbs.
and now the brake and tail lights are really bright.
now when i hit my brakes when the running lights are on
there is a significant change in brightness.
ebay for $22.00


1157 pure white led projector bulbs