I know exactly where to start with diagnosing in all other aspects of the basic engine diagnostics. But where do i start with cruise control? mine never worked and got a long trip coming up. where do i start? it just doesnt work AT ALL no, nothing!

thanks opc orn:

 

when you pust the button on the sterring wheel does the light come on the intraument pannel?

 

I believe theres a vacuum line that goes to the cruise control unit under the hood. Check and see if thats connected and getting vacuum.

 

If your a hot blond thats ok

If the cruse dosn't turn on check all the fuses with a test light first.

If it powers up but will not hold speed, check for a loose vacume line, a common place is about the middle of the intake manifold, there is a vac supply that always pops loose.

 

Don't think an 88 has a dash light but that would be a good place to start on a 99+ XJ.

 

Hi, I have a complete repair manual (PDF 164k) for a 1994 jeep and can email you a copy of the procedure for checking and repairing the cruise if you want...Tj

P.S. if anyone else needs repair manual info just email me at Trekkerjmm@comcast.net and ill send it. I bought it (Complete service repair manual from the dealer) off eBay for $4 and it is extremely detailed...Tj

 

woops my bad blue but a correction on the VAC lines cause when mine came loose going to the main resivoir i tried CC and it worksed fine i guess it could be a different line so idk

BTW: the line on mine was right next to the battery on the fender side

 

Thanks guys, i will check all of that and yeah, only one of ya'll realized that i have a 88. lol guess i am not the only blonde! anyways have anymore suggestions let me know, but right now i got to go replace my lower radiator hose and valve cover gasket! fun!

 

The only reason I posted the dash light absence is I take a special interest in Renix era Jeeps and yours qualifies. Hope you get the CC fixed or already have.

 

I saw you had an 88 but thought they might be similar...Tj

 

I had a 96 caviler a while ago and I had to replace the head gasket and with taking it apart, it had a comp box with a cable that ran to it, it was a seprate throttle cable, but no vacum hose.

I guess what I am trying to ask is how does it work, i am able to fix things better if i know how they work in the first place.

 

There is a servo connected by a cable to the throttle linkage. The servo has a vacuum line that holds it at whatever setting on your stalk the button is depressed at. There is a part of the brake light switch which breaks the buttons connection that allows the servo to disconnect from the throttle linkage. The vacuum operated servo has a diaphram inside it that often goes bad and will then fail to hold the vacuum. That is about my extent of the operation of the CC. HTH
Blue

 

Must likely a vacuum line

 

If your controls that change the heat from coming out your vent or defrost is workin right than most likely it aint the vac line but i could be wrong. But I have the same problem and the controls dont work on mine 98 and my light works.

 

not that i know if this is how yours is but my 78 chero full size had that problem to. It was the rubber inside the cc mod that killed mine. rebuilt that and she held vaccum ever sence, still works great my friend said who i sold it to