1965smd

Hello - brand new to the CF! Glad this site is established and available. I searched for "cruise control" and found no obvious hits...so I will post this question with apologies is there is history/content that I was simply not able to find:

I have a 99 JGC Laredo, totally factory, 138K, 2WD in fine shape, just purchased. A few things are needed, but the main issue for me at this time if the Cruise will not engage. Cruise button on left side of steering wheel triggers green indicator light on dash, but alas, no matter what speed (tried anywhere from 25 - 65) the cruise will not engage.

I am a strong intermediate "wrencher" with some electrical experience, so any diagnostic advice at any level is welcomed in response to this post.

Thanks to all.

SMD

Bustedback

Make sure there is a vacuum signal to the cruise control servo.

dave1123

Best place to start. Then check to see if the cable to the throttle is connected.

1965smd

Checking the vacuum signal to the cruise control servo is outside of my knowledge - but I am reasonably sure I can determine if the throttle cable is in fact hooked up. Thanks guys.

Bustedback

With the engine running pull the vacuum hose off of the servo and feel if there is any suction at the hose. Simple.

freegdr

Good reading here after checking vacuum ....http://www.jeep4x4center.com/knowledge-base/index.htm

1965smd

I took the battery and battery tray out and fully inspected all the vacuum hoses and they *appear* intact and connected.......unit is plugged in, and the cable leading to the throttle is attached at the throttle.

While I have it apart, I will try the vacuum test that BustedBack described......will advise if there is suction.

BTW: What is that electrical connection that leads to a round plug in the middle of the battery tray? I could not disconnect and just cut the wires.........I can splice them back, but wondered what it does and is it worth the effort?

Thanks!

1965smd

FREEGDR: thanks for the link to The Jeep Knowledge Base!

Bustedback

Splice those wires to back together! That is the battery temperature sensor and it tells the PCM if the battery is being over charged.

1965smd

Got everything put back together - I managed to get the CC to engage only intermittently - once with the "resume/accel" button.....and then was able to coast or accel......and once with the actual "set" button. 8 times of ten, the system will not engage. I am leaning toward pointing the finger at the controls on the steering wheel. Do those things get sticky/dirty and need spraying down with electrical cleaner? Or are they serviceable at all?

1965smd

BustedBack: yeah....as I put it back together, I spliced the sensor back in and taped it up completely. Thanks for the info. When I started the truck with it disconnected, the "Check Engine" light illuminated - figured that was why and it went off once I had it reconnected.

Bustedback

Oh yeah, years of people's grimey snot filled fingers may have gummed them up. They are simple to replace, don't bother trying to clean them. They are not like normal switches the complete a circuit. Each button has a different resistance value and the computer can determine what function is requested by what the resistance is.

1965smd

I see. Best place to pick up replacement switches?

Bustedback

Look at www.rockauto.com or maybe try the boneyard.

freegdr

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