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William Herren
William Herren, OWNER
Category: Medium and Heavy Trucks
Satisfied Customers: 26
Experience:  Mechanic at HERREN INDUSTRIAL GROUP
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We have 08 Freightliner m2 112 with a mbe9000 engine. Engine

Customer Question

We have 08 Freightliner m2 112 with a mbe9000 engine. Engine fan stays on with or without a/c running. With truck turned off fan is locked. With key on engine off fan spins free.At startup fan engages. We have four codes spn 647 fmi 4, 647 fmi 5, 1071 fmi 4,1071 fmi 5. All codes are NOT active they are logged. All deal with fan open or ground issues. Our high side psi switch power wire has 3.6 volts going to it. At fan sol we have 12.7 volts. Mitchell One wiring diagrams do not show complete wiring. We need wiring for mbe 9000 engine to m2 systems on truck( bhm,chm and mcm systems) We need to know where grounds are and harness plugs are. ddc troubleshooting is for active faults. Ours are logged. Thanks Phil
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Heavy Truck Mechanic I'm going to connect you with knows all the tricks and shortcuts. Is there anything else important you think the Heavy Truck Mechanic should know?
Customer: no
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Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Customer: replied 1 year ago.
our mbe 9000 has jake brakes on it but no engine fan over ride switch.
Expert:  Daniel Wilson replied 1 year ago.
Hi Phill my name is***** will be glad to try to help. Let me see what I can pull up for diagrams for you. Is this an MBE900 or MBE4000? Wasnt sure if the 9 or the extra 0 is the typo. Would like to know before I spend the time looking up the wrong information...
Customer: replied 1 year ago.
Expert:  Daniel Wilson replied 1 year ago.
Thanks, ***** ***** gather some schematics shortly... In the meantime here are some other helpful troubleshooting links.Troubleshooting 1Troubleshooting 2
Expert:  Daniel Wilson replied 1 year ago.
Click on the link below for the diagrams i uploaded for you. Please remember to rate my service as that is how the site credits the experts for their time helping on the site.Diagrams
Customer: replied 1 year ago.
already went thru troubleshooting 1 it was useless. couldn't open number 2 please resend
Expert:  Daniel Wilson replied 1 year ago.
I was gathering schematics I said and just pulled up the fan circuit pinouts.... I see where this is going already... Im going to opt out and someone else can help you
Expert:  William Herren replied 1 year ago.
I would like to help you resolve this problem
Customer: replied 1 year ago.
was sent mbe side of harness. need freightliner schematics
Customer: replied 1 year ago.
need freightliner wring side
Customer: replied 1 year ago.
sorry wiring lol
Customer: replied 1 year ago.
ok anyone still here?
Customer: replied 1 year ago.
William can we resolve this ????
Expert:  William Herren replied 1 year ago.
I am still here.
Expert:  William Herren replied 1 year ago.
I would like you to inspect your connectors at the power distribution module located above or near the left front tire. Remove each connector and inspect for burnt connections. Please let me know what you find and send pics of each connector once disconnected. Please disconnect batteries before performing inspection.
Customer: replied 1 year ago.
Disconnect batteries. Inspected power cables at distribution module. Perform ten pound pull test and inspect sockets and plugs. Green plug pin B has a old repair. Someone cut the wire and spliced on to the power cables running a 30 amp fuse. Green plug socket and plug are burnt but not melted. Other pins look ok.
Customer: replied 1 year ago.
We have also inspected BHM port B2 for engine fan checked ok. Could our logged fault codes be from a/c system, engine temp or Jake brake being used. We only have 3.7 volts at power wire to a/c high psi switch. How many volts should we have? We will be out of our shop until Monday. I may just pay to talk to you to make this easier. Have a good weekend and we will connect Monday. Thanks Phil
Expert:  William Herren replied 1 year ago.
Have u tried a test control head for the hvac?
Expert:  William Herren replied 1 year ago.
That problem has occurred several times and it was either the pdm which u said did have signs of burnt terminals. Which it can also damage inside the pdm. I believe u will find ur problem is the pdm or the hvac control head.

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