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Cruise control not working

I have a 96' Freightliner FLD120 Since I have had this truck the cruise has only worked at an idle. I have been told that many different things could be the culprit, but is there a way to diagnose this and save me from throwing parts at the truck?

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I have a 95 Freightliner and have owned it 10 years. The two most common causes for the cruise not working are the clutch petal switch and the parking brake switch. The clutch switch is located under the dash above the clutch pedal. Check to see the pedal is depressing the switch when released. I have had to epoxy a quarter to the pedal to fully depress the switch. The switch can be tested by detaching the wires and hooking them together BUT remember the cruise will not turn off by depressing the clutch pedal in this condition. The parking brake switch is attached to the yellow parking button behind the panel. Remove the top panel on the dash where the defroster outlet is and look for a round switch plumbed into the air line into the parking brake valve. It has two wires attached to it. Start the truck and turn the cruise on bumped up idle. Pull off one wire. If the cruise comes off stop. If it continues attach one wire to the other. The cruise should come off. The cruise will no longer work when the parking brake is on but WILL work going down the road. If this is the case replace the switch. Hope this helps.

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My 2000 FLD has two speed sensors, one for the CC and one for the speedometer. Maybe you have a bad sensor or wiring to the sensor. My cruise control was messing up last month and I found a broken wire from the speed sensor.

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Under the cup holder there's a panel. Remove that panel and you'll see the air system manifold. On this manifold there are 5 or 6 switches that look like automotive oil pressure sending units. These could be your problem. They're $9 a piece and I've dealt with a truck that didn't have cruise going down the highway but did parked and I've also dealt with a truck that had an audible air leak. Replacing these switches fixed those problems. I have a schematic for these manifolds that tell you which switch does what but I don't see an add file link.

If you'd like this schematic I'll be glad to send it to you.

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Hello,I have a 05 century with the same problem. my truck has 6 switches,can you tell me which controls the cruise or do you have the schematics for this one Thanks

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You may also want to check and see if your brake pedal is working in full range, that is, is there anything preventing it from coming all the way up. ie dirt, rug, maybe just rusty pivot.

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I have a 1994 fld 120. Idle up mode works after changing the parking brake air switch. Cruise control still does not. My clutch switch seems to be functioning (used a continuity tester and pressed/depressed pedal). Where would the switch for the brake pedal be?

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X2 on the speed sensors. You most likely have two sensors one for the speedo one for the ECM. If it works while parked it is in PTO mode where no speed signal is needed. Once moving the engine load does not allow PTO mode. So the ECM uses the speed signal to run in cruise control if no signal it won't work. If your sensors are thread in verify adjustment. I thread them in until bottomed then back out 1/8 to 1/4 turn. Check sensor continuity should be 900 to 1800 ohms if I remember right. Try switching the connectors and driving if cruise works but no speedo there's your problem good luck

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I have a 2004 t600 with no cruise or engine break? Any ideas on what would cause mine?

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I had the same problem, changed all the air switches, no help. Took it to a Freightliner dealer, after 2 days they found all the ground cables between the cab and frame were corroded. Put on new grounding cables and worked fine.

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07 freightliner cruze control does not work when i put the cruze control switch on park lights goes off take cruze control switch off park light come on help please

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i have 2005 fl colombia , i have the same problem with cruise control , any one can help please ,

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Cruise just quit on my '99 T800. Worked fine when first warming up, then would not engage when started the engine later that afternoon.

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That's the same problem with my 01 Columbia. 60 series. But after awhile just quit completely. Even Detroit Diesel can't find the issue.

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Joseph Murphy will be eternally grateful.
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