HVAC / Cruise Control Issues

[Hickory_Briars]

Hi,

I've been running my mom's old 99 TJ while my F150 is in the shop and would like to fix a few odds and ends for her as a thank you. One thing at the top of my list is to get her HVAC back going strong (south Alabama summers are brutal). I've done a bit of research and have found that there is a connection between cruise control and vent selection (a common harness I believe?). Her cruise control will turn on (light comes on the dash) but will not activate.

Does this mean I am likely going to need to replace that common harness? Does anyone have a part number on that harness? Is it a relatively easy job?

Side note, she had all kinds of ignition trouble and has had people all in the steering column working on that. However, I believe this problem pre-dates the ignition issues.

One other question, while they were working on it they lost a lot of the screws for the dash and door panels. Does anyone know of a kit I can buy with replacement hardware?

Thanks!

 

[imahnu]

It seems to me (I just installed cruise control in my Jeep, but someone else more knowledgeable may come along), that it could be a vacuum issue. The vacuum line is connected to the AC system as well as cruise control. I'd start with that before worrying about any electrical issues that may be causing your issue.

The vacuum line runs from the CC servo to the driver side of the engine and then up and over the engine along the fire wall main harness to where it splits to the AC system and then continues down to a vacuum box underneath your battery tray. If you have any leaks or cracks in the fitting or lines you can have the issues you're experiencing.

Hope it helps!

 

[CharlesHS]

Trace out the vacuum tubing looking for cracks in the lines or disconnected fittings.

 

[CODE5]

Did you have any luck @Hickory_Briars with the vac lines?

 

[elkivory]

FWIW I had similar problems when I bought my 06 LJ. I got lucky while looking at the vacuum line CharlesHS referenced in his post. I pulled one end and blew through line, just happened to feel air on my arm and found a pin hole in line. Replaced the line. It is cheap and easy fix. My AC was not working right and cruise was intermittent.