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Jeremy, Certified Truck/Bus Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 3380
Experience:  ASE Med/HD Truck Technician, NATEF Diesel Engines and Electrical/Electronics Technician, EPA 608/609 HVAC Certified, Steering/Suspension and ABS/Brakes Technician
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I have a 1998 Freightliner century. The fan will not cycle

Customer Question

Hi I have a 1998 Freightliner century. The fan will not cycle when the ac is on. It will come on if you pull the fuse for the fan. Can you help.
Submitted: 2 years ago.
Category: Medium and Heavy Trucks
Expert:  Jeremy replied 2 years ago.
My name is ***** ***** I will assist you. Are you getting any codes on the dash at all? It sounds like the solenoid is working correctly. The only problem that will stop the signal to reaching the ECM is the binary switch on the A/C system. When it goes bad, it will engage the fan for coolant when the engine is hot, but will not engage it for A/C. I would replace the binary switch. You don't need o drain the refrigerant. You should be able to remove the switch and replace the o-ring. The switch screws onto a Schroeder type valve. That switch is the one closed to the condenser on the A/C system. Usually on the passenger side, the one on the high pressure line, not the low pressure one next to the drier. It will have a plug with 4 wires going to it. __________________________________________________________________________________________________________________________You want a 5 star service and I want to provide a 5 star service. Please consider that I don't know your skill level as well as I can't see,touch, smell, hear, or taste the vehicle/machine in question. Please provide as much detail as possible and I will provide as much back.The system DOES NOT automatically give me credit from your deposit. A rating is REQUIRED. You are rating me for the information I provide,not the website. I have no control over the site fees, site errors, category errors, or how long it took for a response for these reasons.I am not an employee of this website, so please rate with a POSITIVE (green) rating for me to get credit for assisting you. You still paythe website for negatives or by not rating at all. I just get nothing from that payment you made. So please rate each answer I provide.I want you pleased with my service to you so please inform me before rating negative (red) and I will do my best to make it right. Followups for same question are always free after ratings have been made.I do have many workshop manuals, diagrams, etc that I pay to get access to out of my pocket. If one is needed, please ask and I will giveyou an offer at my technician discounted cost to you for such manuals. I never charge above that cost.Thank you for allowing me to assist you through Just Answer!Jeremy
Customer: replied 2 years ago.
On the century it doesn't have a binary switch only if you do the binary retro fit which is a update from Freightliner. The high pressure switch and the low pressure switch are new and they are located at the right side of the cab at the bottom. They are both 2 wire switch and both are new. They also run to the acpu unit. There is also no codes. And the fan works the way it should with engine temperature.
Expert:  Jeremy replied 2 years ago.
I didn't notice the year. The 2002 on up has the binary on a lot of them... What engine is in this? I'm going to pull the diagram.
Customer: replied 2 years ago.
Yes you are correct. This is a Detroit engine and I do have DDL but it doesn't help in this matter.
Expert:  Jeremy replied 2 years ago.
DDDL won't help unless you have a engine code. You will need Freightliner Service Link. What version of Windows are you running? I'm going to see if I can get Freightliner Service Link loaded, if Freightliner will let me pull it. It will tell you if the ECM sees the command from the A/C to engage the fan or not. The fan is controlled from the ACPU on that year, too. I believe that was the first year they used it. HERE is Freightliner Service Link. Since you have DDDL, I'm presuming on a laptop? If so, load this up, shut down DDDL, and run this. This is the offline version so no license is needed for it. Once it is p and started, it will ask for a VIN, put that is and it should select the settings for the vehicle. Then once in it, you can see the ACPU and open it. In it, it will show the A/C on/off state and the fan on/off state. It will give you the notice of if the fan is commanded on. If so, then you know the issue is somewhere on the output of the system. The way that should be done is the signal goes through the high pressure switch to the ECM and the ECM commands the A/C clutch and the fan. So check that you have voltage going in and out of the high pressure switch. Also, I am uploading the Workshop Manual section for the fan clutch as well. It lists all the styles and how the power is routed. They are routed the same except one, which I don;t believe that year used and that was the Eaton style that has the 4 wire solenoid and the relay.
Customer: replied 2 years ago.
Ok thank you. I will check it tomorrow and see what I can do with the diagrams. I had the truck at Freightliner today and they said they couldn't get the service link to connect to it. But I never have a problem connecting DDL to it.
Expert:  Jeremy replied 2 years ago.
ServiceLink and DDDL connect to different parts of the truck. The ServiceLink connects to the chassis and all the modules on it, DDDL sniffs for the ECM and connects direct through it, although it goes through the body controller. A lot of the times the dealer tries to use the new DDDL 8 to connect through ServiceLink instead of using the stand alone, because that is what most techs are trained to do. Try doing it by itself and hopefully you won;t have any issues with it. Let me know what you find out with it. Thanks.
Customer: replied 2 years ago.
hey Jeremy I have installed service link but I don't see any where to put in a vin number. I have never used this program before. the only thing I see is start service link. I click it but nothing happens.
Customer: replied 2 years ago.
Hey thanks for your help. I'm not going to continue looking for this problem. We sent it out yesterday and the engine went out in the truck.
Expert:  Jeremy replied 2 years ago.
I apologize, I got hurt at work and was occupied. Someone else lack of attention when they rolled up in the yard. They ended up hitting me. I couldn't jump out of the way fast enough. On the program, did it open in internet explorer? It only works if you have internet explorer as a your default. It doesn't work in firefox or chrome. I learned that the hard way when I first got it. When it opens up, you should have had a connect box in blue on the left. You click it and the next screen opens that says vendor. This is for the adapter you are using. You select the adapter then click the 2 boxes for the protocols and select save settings. Next screen will give you the vehicle serial number (if it first reads on it's own) or the option to put in the VIN. You put in the VIN and select next. Then it will do it's connections. You will get list of ECU's on the left with tabs on the top that say General, Faults, and Templates. What you then do is selct the ECM on the left whether it be engine (which is limited to only the signals the engine is sending for they all use their own software), ICU, A/C, Vehicle, ABS, etc. For the fan clutch you would select engine and then you will get all the actions the engine is doing, if A/C fan is engaged, etc. Select Template at the top and it will open up to the parameters. There you can activate the fan, deactivate it, tell the A/C clutch to engage, disengage, etc. It's a pretty good program to use for the Freightliners.