Mgdoug3

I know this problem pops up a lot, but the search button has not yielded me any results. I have checked my vacuum (15" of vacuum), brake light switch passed the continuity test, and CC switch seemed to ohm out. My CC light comes on but does not set. When I use my vacuum test, all lines hold vacuum without leaking down. The servo doesn't leak down either. My horn works and if my air bag light is working, it's not lit up.

When I checked pin 2 on the connector to the switch, it only shows 0.06 volts with the CC on. The FSM says to check for battery voltage so I'm assuming that it should read 12 volts. According to the FSM if the connector doesn't show voltage to test the brake light switch but that checks out. With all that said, what do I check next? With the FSM, I'm stuck in an infinite loop. I think I must have a wire shorting out and not letting current flow through the wire.

Mgdoug3

Bump. Any suggestions?

Mgdoug3

I hooked up a scanner and I can activate the servo and the relay passed the test.

bluejeep2001

Pin 4 is the system ground pin 3 gives 12v into the system thru the brake switch when not being pressed pin 1 is the vacuum soln control probably gives 12v when set...pretty sure you need to be over 35mph before it will engage pin 2 is the vent soln control prob gives 12v when you change settings... ensure you have a good vacuum source available at the valve

Mgdoug3

With the scanner I can turn on the servo and move the cable to the throttle body. It seems like mechanically everything is working the way it should. I went to the junk yard and tried a different control switch but I still could not set the speed.

Mgdoug3

I had a thought just a moment ago. I went out and checked the continuity on the clockspring. I only have continuity on three of the four wires. The brown with red stripe doesn't have continuity. I'm assuming this is the wire to set the CC. Hopefully a new clockspring will fix my issue.

Guywitha92

It doesn't work on my 92 either. Let me know if you figure it out

bluejeep2001

According to the print the brown/red wire should be pin 3 on the cruise control servo connector...it should bring in 12v through the closed contacts of the brake switch...if you step on the brake the switch opens and stops this 12v signal you might have to build a test light to check this because the circuit may not be powered when you are below 30 mph.

bluejeep2001

Did some checking on my 01 today...the servo and wiring is the same .If your controls are on the steering wheel then you go thru a clockspring ...if your controls are on the handle then no clock spring. Made some wrong assumptions.. I thought I would have some voltage available on some circuitry but no....Since all the power comes out of the pcm...the system is dead until at least in gear probably and moving at the minimum cruise control speed approx. 30-35. Mine works so I took the connector off today and checked for voltages...all minimal...aprox 0.10v dc With the servo disconnected I can get the green cruise light to come on for a second or so when the on button is pressed then it goes out. It will not come on again until the jeep is shut off and the system resets. With the jeep running but in park I cannot get any voltage between 1/2/3 and ground (4)...even when I get the green light on for a second...therefore the prerequisites have not been met either not in park or not enough speed on the rear wheels or both. I would bypass all your existing vacuum lines unless you are are sure you have vacuum at the connector going into the servo...Hitting the brake does not turn off the green light when all connected so I don't know how the system sees the servo hooked up..the prints may be too basic and not actual system schematics

Mgdoug3

My cruise control is on the steering wheel. I'm fairly sure it's the clock spring. I should have continuity on all four wires of the clock spring for the cruise control but only have 3. The brown with red stripe does not.

Mgdoug3

I fixed my cruise control issues. New clock spring didn't work. I kept getting a P1899 code so I took apart my NSS switch and cleaned it throughly. The Jeep would still start in any gear (something I didn't notice until I looked up the code today). I looked for jumper wires but didn't see any. I unhooked the NSS and the Jeep wouldn't start. Removed the NSS again and looked at the wires closely. I noticed some old black tape near the connector and took a closer look. Someone a while ago spliced two wires together. Unhooked them and taped it back together. Hit the road and the cruise works like a charm.

So to sum up, I was getting a P1899 code and the computer thought the vehicle was stuck in park and not letting the cruise control engage. Jeep now only starts in park and neutral. Someone's easy fix cost me a week of pulling my hair out and all the NSS needed was a thorough cleaning.

Guywitha92

Thanks for the update. I will try cleaning my nss this weekend

damelloman

Mgdoug3 - Your issue was the exact issue I had. Long story short... I was trying to fix my cruise control. I also have a 96 XJ 4.0 Auto 4x4. After checking the servo, steering wheel switch, clock spring I read your post. I realized I also had a check engine light... then verified I had the same code as you. It makes sense... if the PCM doesn't know you are in drive why would it let the cruise control activate? I used the tutorial here: http://bc4x4.com/tech/2010/jeep-neut...commentsanchor which made it super easy. I found the exact same spliced wire. So instead of the previous owner replacing the NSS (Which they thought was bad) they just spiced those wires which made it start in any gear, broke cruise control, and gave me the check engine light. My NSS actually had exposed wires right where it comes out of the NSS. You couldn't see it unless you disassembled the entire unit. Once those wires were covered (Electrical tape/lighter) and I unspliced that wire my cruise control worked, I could only start in Park and Neutral and after some miles the check engine light went away! Thanks so much Mgdoug3. I may have wasted many MANY more hours on this if I hadn't stumbled upon your post.

Mgdoug3

Sounds like you figured it out quicker than I did. Glad my thread helped you out.