A few months ago i replaced my power brake booster, master cylinder, and rear brake cylinders on my 93 XJ.
I finish the job, bleed the breaks and put my tools away only to see that my break lights were on and I wasn't touching the break pedal.
RED FLAG= brake light switch! Thats what i was thinking.
So I adjust it to where my lights turned off.
A few days later I get on the freeway and turn on my cruise control which is working great as usual. I hit a small pot hole and my cruise control shuts off and wont turn back on. It works every once in a while now but usually shuts off when I hit a pothole or bump.
So I installed a new brake light switch a week ago and took it for a test drive.
The cruise control turned on for me once but shut off randomly and wouldn't engage after that.
Any ideas will be appreciated!
Thank You

 

Check for a loose or cracked vac line. Also check to see if your heat is stuck on defrost. Mine did that and the vac line behind the battery had a hole rubbed through from the battery. Everything works good now.

 

My heat works fine and isnt stuck at all.
The vaccume line you are talking about, is it under the battery tray?
which vaccume lines can effect the cruise control?
thanks for your feed back

 

It sounds like the brake light switch is turning off the cruise control, it may be adjusted to close to the pedal.

 

I also think your problem is the brake light switch. Your FSM (or Haynes manual) will tell you the correct way to adjust the switch.
Dan

 

i looked through my Hanes book and it said something about 1/8" gap
but it didnt really make any sense to me.
when i looked under there it seems that no matter where i put the plunger it is always touching the brake petal.
any ideas
thanks alot!

 

On mine, it said after installing the switch to pull the brake pedal up until the clicking stops. That's a ZJ though so it might be different.
Dan

 

i read something like that about the clicking in another forum.
but idk what clicking to listen for because when i put mine in it made no clicking noise whatsoever.
i guess my question is what clicks?

 

The brake light switch has a ratchet type mechanism in it, and when the brake pedal is pulled up it pulls up the plunger on the new switch making the clicking noise as it sets the switch at the proper dimension. At least that's the way mine is.
Hope that helps explain it.
Dan

 

i see what you are saying but im pretty sure that doesnt apply to mine because there really is no clicking noise when i press the brake petal. i have a feeling it is a bad vacume line because one is a bit cracked
im going to autozone to buy some tomorrow, i will put them on and post what happens
thanks for the help

 

No, the clicking happens when you pull up on the brake pedal to set the switch after installation. It doesn't click when you press down on the pedal. Sorry if I had you mixed up.
Dan

 

hmmm. i went over my Hanes manual and it said nothing about adjusting it according to a click.
so your saying you install the switch then pull the pedal toward the seat and wait for the clicking to stop or start?
thanks Dan its very much appreciated!

 

That's how the manual said to do it on my ZJ.
Dan

 

I'm no expert by any means, but I happened to notice on my '89 XJ, there is a CC computer, seems like it was yellow, mounted to lower panel below steering wheel that has some adjustment slots on it. Don't know if the newer models like yours have it too though or, if it does, if any of the adjustments might fix your problem.

Just thought I would mention it just in case.

GOOD LUCK!!!

 

great. thanks for the tip.
ill take a look at mine in the morning and see if it has one.
im beginning to think it might have somthing to do with the vacume lines
but thanks for the tip
i will diffidently check it out!