99 freightliner cruise control not working

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cruise not working

Discussion in ' Trucks [ Eighteen Wheelers ] ' started by gunner76 , Nov 19, 2014 .

gunner76 Medium Load Member

We have a '99 FL112 Freightliner and the cruise has stopped working, this also means that we lost the ability to bump up the idle. Trying to figure out what the problem is and here is what I've found so far. This truck is set up so when the cruise switch is in the "on" position the jakes will only turn on when the brake pedal is pushed, when the cruise switch is off the jakes will engage when you let off the throttle. Right now when the jakes are on standby they will turn on when you let off the throttle no matter the position of the cruise switch. Also when the cruise switch is off you can hold the set/resume switch to run a diagnostic scan for any stored codes. I thought it might be the cruise on/off switch so I replaced it and there was no change. Next I replaced the stop light pressure switch that is mounted on one of the airvalves on the firewall and that made no difference. I don't think it is the set/resume switch since I can activate the code scan feature using it and I don't believe it is the switch down by the clutch pedal because if that was bad the jakes shouldn't turn on either. Anybody have any ideas on what it could be?  

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Alaska76 Road Train Member

Do the brake lights work? Many cruise systems rely on an operational brake light circuit, as that is one way to cancel the cruise control.  

Alaska76 said: ↑ Do the brake lights work? Many cruise systems rely on an operational brake light circuit, as that is one way to cancel the cruise control. Click to expand...

JohnP3 Road Train Member

One thing you could test is the speed sensor on the back of the transmission, if you have a Ohm meter, test both coils one should be around 900 and the other between 1100 and 1400, if you do not have a meter swap the leads, and inspect the wires. You may need to have it put on a computer to find the problem, testing each switch, diagnostics by the ripping and tearing method very rarely works, and is expensive. The 900 Ohm coil lead should go to the computer. You want to tell us what engine you have!  

GrapeApe Road Train Member

For high idle, the speed sensor should not be an issue because the truck should not be moving. The VSS is big a factor for the cruise control to work properly, but the high idle usually works when the VSS fails. I'm assuming that it's a Cat if you pulled flash codes from the cruise switches? If so, then the set/resume switch is working. To test the on/off switch, turn it on and try to pull codes again. If you can, the ECM is not seeing the on/off switch. It will only pull flash codes with the switch off, so if it wont pull them with the switch on, those 2 switches and wiring are OK. If it pulls code with the switch on, diagnose the problem in the on/off switch circuit. You have a parking brake switch and clutch switch circuits to check as well.  

Trckdrvr Heavy Load Member

I think fuse..  

GrapeApe is correct, it's a C12. The on/off switch for the cruise is also working fine because I can't run the code scanner with the switch in the on position. By clutch switch do you mean the spring loaded one that the pedal pushes against? I figured that if that switch was stuck in a position that wouldn't allow the cruise to work that the jakes also would be dead.  

sunsation288 Light Load Member

GrapeApe said: ↑ To test the on/off switch, turn it on and try to pull codes again. If you can, the ECM is not seeing the on/off switch. It will only pull flash codes with the switch off, so if it wont pull them with the switch on, those 2 switches and wiring are OK. If it pulls code with the switch on, diagnose the problem in the on/off switch circuit. Click to expand...

sunsation288 said: ↑ Just a question , i try to figure what mean .... pull flash codes ? thanks in advance for taking time Click to expand...

postmandav Medium Load Member

We had a Volvo at a former company that had an issue with the cruise not working. I happened to be driving one day and accidentally pushed the clutch pedal up. All of ;a sudden the cruise started working. Maybe you have to much freeplay in your clutch pedal.  

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Freightliner Cruise Control Not Working: Quick Fixes

Freightliner cruise control issues often stem from faulty wiring or a malfunctioning brake switch. Regular maintenance can prevent these problems.

Freightliner trucks are known for their durability and advanced features, but even the best systems can encounter issues. One common problem is the cruise control not working, which can disrupt long-haul drives. Causes can range from electrical wiring issues to a malfunctioning brake switch.

Addressing these problems promptly is crucial for maintaining driver comfort and safety. Regular maintenance and timely troubleshooting can help keep the cruise control system operational. Understanding the root causes can save time and money, ensuring that the truck operates efficiently on the road.

Table of Contents

Introduction To Freightliner Cruise Control Issues

Freightliner trucks are known for their reliability and performance. Yet, like any vehicle, they can experience problems. One common issue is the cruise control not working. This can be frustrating for drivers, especially on long hauls.

Understanding the symptoms and importance of cruise control is crucial. It helps in diagnosing and fixing the problem efficiently.

Common Symptoms Of Malfunction

• Cruise control fails to activate : The system doesn’t engage when the button is pressed.
• Inconsistent speed maintenance : The truck struggles to maintain a consistent speed.
• Unresponsive controls : Buttons on the steering wheel or dashboard don’t work.
• Warning lights : Dashboard lights may indicate cruise control issues.

Recognizing these symptoms early can save time and money. It helps in addressing the problem before it worsens.

Importance Of Cruise Control For Long Hauls

Cruise control is a vital feature for long-haul truckers. It helps in maintaining a steady speed, reducing driver fatigue. This feature allows drivers to focus more on the road, ensuring safety.

Additionally, using cruise control can improve fuel efficiency. It helps in maintaining a constant speed, reducing fuel consumption. This is especially important for long journeys where fuel costs can add up.

Lastly, a functioning cruise control system can enhance the overall driving experience. It provides comfort and convenience, making long trips less stressful.

Initial Diagnostics

If your Freightliner cruise control is not working, it’s crucial to perform initial diagnostics. This step helps identify any basic issues before diving deeper. Following a structured approach can save time and effort. Let’s start with the basics.

Checking The Basics: Fuses And Connections

The first step is to check the fuses and connections . A blown fuse or loose connection can cause the cruise control to malfunction.

• Open the fuse box and locate the cruise control fuse.
• Inspect the fuse for any visible damage.
• Replace the fuse if it appears blown.
• Check all related electrical connections.
• Ensure connectors are secure and wires are intact.

If the fuse and connections are in good condition, the issue might be more complex. Proceed to the next step.

Diagnostic Tools And Error Codes

Using diagnostic tools can help identify specific error codes. These tools provide valuable information about the cruise control system.

• Connect the diagnostic tool to the vehicle’s OBD-II port.
• Turn the ignition key to the “On” position.
• Follow the tool’s instructions to scan for error codes.
• Note down any error codes related to the cruise control system.
• Refer to the vehicle’s manual for code definitions.

Common error codes might point to sensor issues or software glitches. Addressing these codes can resolve the problem.

Regular maintenance and timely checks can prevent cruise control issues. Always stay proactive in vehicle care.

Troubleshooting Electrical Problems

When your Freightliner cruise control is not working, the issue may be electrical. To fix it, you must troubleshoot electrical problems. This involves inspecting the wiring harness and testing the cruise control switch.

Inspecting The Wiring Harness

The wiring harness connects many electrical components in your truck. A damaged or loose wiring harness can disrupt cruise control.

First, locate the wiring harness. It is usually under the dashboard or near the steering column. Check for any visible damage, such as frayed wires or loose connections.

Use a multimeter to test the continuity of the wires. Ensure there is no break in the circuit. If you find any damaged wires, replace them immediately.

Important: Always disconnect the battery before inspecting the wiring harness to avoid electric shock.

Testing The Cruise Control Switch

The cruise control switch is another key component. If it is faulty, the cruise control will not work.

Start by locating the cruise control switch on the steering wheel or dashboard. Use a multimeter to test the switch.

Set the multimeter to the “ohms” setting. Press the cruise control button and check the reading. It should change from infinite to zero. If it does not, the switch is faulty.

Tip: Replacing a faulty switch is usually straightforward and can be done with basic tools.

Regularly inspecting these components can prevent cruise control issues. Keeping your wiring harness and switch in good condition ensures a smooth driving experience.

Air System Checks

If your Freightliner’s cruise control isn’t working, one key area to inspect is the air system. The air system plays a crucial role in the vehicle’s overall functionality. Ensuring it operates correctly can solve many cruise control issues. This section covers two primary checks: verifying air pressure levels and examining the air solenoid operation.

Verifying Air Pressure Levels

Start by checking the air pressure levels in your Freightliner. Proper air pressure is essential for the cruise control system to function.

• Locate the air pressure gauge on the dashboard.
• Ensure the pressure is within the normal range.
• If the pressure is too low, your cruise control won’t work.
• Use a manual gauge to verify the dashboard reading.

Low air pressure can indicate a leak or other issues. Inspect all air lines and fittings for leaks. Use soapy water to detect small leaks. Bubbles will form at the leak point.

Examining The Air Solenoid Operation

The air solenoid is another critical component. It controls airflow to various parts of the truck.

If the solenoid is faulty, it needs replacing. A malfunctioning solenoid can disrupt the cruise control system. Replace it to restore full functionality.

Sensor Inspections

Freightliner cruise control issues often stem from sensor malfunctions. Inspecting these sensors can help identify and fix the problem. This section covers two critical sensors: the speed sensor and the brake pedal sensor.

Speed Sensor Functionality

The speed sensor plays a vital role in cruise control. It monitors the vehicle’s speed and sends data to the cruise control system. A malfunctioning speed sensor can cause erratic cruise control behavior.

To check the speed sensor:

• Locate the sensor near the transmission.
• Inspect the sensor for visible damage.
• Use a multimeter to test sensor voltage.

If the voltage readings are incorrect, replace the speed sensor. This should resolve most cruise control issues.

Brake Pedal Sensor Issues

The brake pedal sensor is another key component. It disengages cruise control when you press the brake pedal. A faulty brake pedal sensor can prevent cruise control from engaging.

Steps to inspect the brake pedal sensor:

• Locate the sensor near the brake pedal.
• Check for loose or damaged wires.
• Test the sensor’s continuity with a multimeter.

If the sensor fails the continuity test, replace it immediately. This will often solve the cruise control problem.

Inspecting and fixing these sensors can restore your Freightliner’s cruise control functionality.

Engine Control Unit (ecu) Considerations

The Engine Control Unit (ECU) is a critical part of your Freightliner. It manages various engine functions, including the cruise control system. If your cruise control is not working, the ECU might be the culprit. Let’s dive into some key ECU considerations.

Resetting The Ecu

Resetting the ECU can solve many issues. To reset, disconnect the battery for 15 minutes. This clears minor software glitches. After reconnecting, test the cruise control again. If the problem persists, further steps might be needed.

Software Updates And Reprogramming

ECUs need regular software updates. These updates fix bugs and improve performance. Outdated software can cause cruise control issues. Check for any available updates from Freightliner. If updates are available, install them promptly.

Sometimes, the ECU might need reprogramming. Reprogramming adjusts settings for optimal performance. Only a professional should handle this task. Incorrect programming can lead to more issues.

Freightliner Cruise Control Not Working? [Here is the Common Quick Fixes]

If your Freightliner cruise control is not working, don’t worry. Simple fixes can often resolve the issue. Here are some common quick fixes to try.

Replacing The Cruise Control Fuse

A blown fuse can cause cruise control to stop working. Follow these steps to replace the fuse:

• Locate the fuse box in your Freightliner.
• Find the fuse labeled “Cruise Control.”
• Remove the old fuse carefully.
• Insert a new fuse of the same rating.

After replacing the fuse, test the cruise control. It should work if the fuse was the problem.

Adjusting The Brake Pedal Switch

A misaligned brake pedal switch can disable cruise control. Here’s how to adjust it:

• Find the brake pedal switch near the brake pedal.
• Loosen the switch’s mounting screws.
• Adjust the switch position until it aligns correctly.
• Tighten the mounting screws.

After adjusting, test the cruise control again. If the switch was the problem, it should work fine now.

Professional Intervention

When your Freightliner’s cruise control stops working, it can be frustrating. Sometimes, the issue might be simple and easy to fix. But other times, you may need a professional mechanic to step in. This section will guide you on when to seek help and what to expect at the repair shop.

When To Seek A Mechanic’s Help

There are specific signs that indicate you need a professional. Here are some of them:

• Warning Lights: If warning lights appear on your dashboard.
• Unusual Noises: Any strange sounds when you activate cruise control.
• Intermittent Function: Cruise control works sometimes, but not always.
• Speed Issues: The vehicle does not maintain the set speed.

What To Expect At The Repair Shop

When you take your Freightliner to a repair shop, a few steps are followed:

• Diagnostic Test: Mechanics run a test to find the problem.
• Inspection: They inspect the cruise control system and related parts.
• Estimate: You will receive a cost estimate for repairs.
• Repair: Mechanics fix or replace faulty parts.
• Test Drive: They test drive the vehicle to ensure everything works.

Here is a quick table summarizing what happens at the shop:

Getting professional help ensures your cruise control is fixed correctly. It saves you time and stress.

Preventative Measures And Maintenance Tips

Freightliner trucks are known for their reliability, but cruise control issues can arise. Preventative measures and maintenance tips can help you avoid these problems. Consistent care ensures your truck runs smoothly.

Regular System Checks

Performing regular system checks on your Freightliner is crucial. Inspect the cruise control system monthly. Check the wiring for any signs of wear or damage. Ensure the switches and controls function properly.

Use a diagnostic tool to scan for error codes. Fix any issues immediately. Regular checks help catch problems early. This prevents bigger issues down the line.

Staying Updated With Recalls And Notices

Stay informed about recalls and notices from Freightliner. Manufacturers issue recalls to fix known problems. Ignoring these can lead to major issues.

Register your truck on the Freightliner website. This ensures you receive updates directly. Regularly check the National Highway Traffic Safety Administration (NHTSA) website for recalls.

Follow the instructions provided in recall notices. This may involve visiting a service center for repairs. Keeping up with recalls ensures your truck stays safe and functional.

By following these tips, you can ensure your Freightliner’s cruise control works effectively. Regular maintenance and staying informed are key.

Frequently Asked Questions

Why is my freightliner cruise control not working.

The cruise control might be disabled due to a blown fuse, faulty switch, or a malfunctioning sensor.

How Do I Reset Freightliner Cruise Control?

To reset, turn off the ignition, wait a few minutes, and then restart the vehicle to see if it works.

Can A Bad Brake Light Affect Cruise Control?

Yes, a faulty brake light or brake light switch can prevent the cruise control from engaging properly.

What Sensors Affect Freightliner Cruise Control?

Speed sensors, throttle position sensors, and brake sensors can all impact the proper functioning of cruise control.

Is There A Fuse For Freightliner Cruise Control?

Yes, check the vehicle’s fuse box for a blown fuse related to the cruise control system. Replace if necessary.

Fixing Freightliner cruise control issues can enhance your driving experience. Always check for common problems first. Regular maintenance can prevent many issues. Consult a professional if you face persistent problems. Proper care ensures your Freightliner runs smoothly. Stay proactive to keep your vehicle in top shape.

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ktripberger - 2/16/2016 08:02 I am almost at a loss. I have a 2000 Freightliner Classic and I can not get the cruise control to work for nothing.

 When I am sitting at an idle, it will work to increase the idle, but as soon as I start driving it won't work.

  The jake brake still works, which should mean that my clutch switch is operating properly. I have replaced all the brake switches.

  I have switched the speedometer wires coming out of the transmission.

  I have also switched out the ECM with a neighbor that I knew the cruise control worked on his truck and still nothing.

  I have no idea what else to try or even check. Any help would be greatly appreciated, before I have to take it to the dealership and have them check it. I would love to avoid that cost. Thanks!

By your description, it sounds like your problem, is in the wiring from transmission MPH sensor up to the engine's ECM.

Just for the heck of it , Have you tried holding up on the clutch pedal while driving (and attempt to set cruise ) = maybe the clutch switch is barely making contact, with truck sitting still; but while bouncing on the road (driving ), the clutch switch signal is intermittent, thus cruise won't engage = just a thought = easy to test.

ktripberger - 2/16/2016 14:02 I have done some digging around on it today.

  There is only one speed sensor with two outputs, I have switched them back and forth and the speedometer reads fine on either output.

  I have checked the continuity on the wires from the speed sensor to the ECM and I have continuity on one output. Both wires from that output have continuity to the ECM.

  I tried every variable with the On/Off switch, held my foot up on the clutch switch and still nothing.

  I believe I am real close to a total loss on this one.

  Thanks for your help guys!

___________________________________________________________________________________________________________________________________________

Ok. I copied and pasted your first thread, so I can see everything on one page .

First, have you owned the truck, when the cruise control actually worked?  (or is this truck  "new to you", and you just purchased it? )

What brand of engine?

Is there a PTO switch, on this vehicle or dash?

The two wires, between MPH sensor and the ECM; Were they twisted together? (or has someone just throw on different wires and they aren't twisted )  = they need to be twisted (they call them a "twisted pair" ).

On your first post you said = it will increase idle  {Does that mean, after you release the cruise "set" button/rocker switch, does the engine maintain that certain RPM, sitting still ?  Example:  it maintains 1250 rpm or whatever, with your hands OFF the dash switches?} or does it drop back down, in rpms?

ktripberger - 2/16/2016 16:35 I have owned the truck for a little over a year and no the cruise has never worked for me. It is a 12.7 Detroit. There isn't a PTO switch.

  The wires are not twisted , but it doesn't look like somebody just threw wires in there.

  They are covered with the plastic wire protector .

  If I am just sitting there at low idle (600 RPM ), and all I do is rock the cruise set (rocker ) switch it will increase the idle to 1000 RPM. I don't have to touch the pedal or anything and it will do that. But if I push the pedal to 1500 RPM and hit the cruise set switch it will stay at 1500 RPM. Hope this helps with your questions, and also thanks for the help.

I'm not a Detroit guy, but on a MPH circuit, it shouldn't matter what truck or engine brand, WHEN it comes to those wires = they should be twisted, but maybe they are twisted inside that "plastic wire protector" or is that protector, just one of those "split-loom" automotive style coverings that anyone can get at an auto parts store (homemade? ) = could you look inside?

Does that covering look like the rest of the truck's wiring? (factory-looking? )

Maybe the "pins" at the ECM's connector happen to be in the wrong port/location and that is why neither your ECM or your neighbor's ECM could "read" MPH {thus neither allowed cruise to work} = just a thought.