I am still chasing down why my AC doesn't work. After several months ForScan has pointed to the HVAC Control Module not communicating with the CAN Bus. Before spending lots of $$$ for a new module I would like to test it out of the truck to see if the problem is the module or the truck wiring / PCM.

I have lots of diagrams, and tools so the only thing I need is a process to test the module.

The module controls all features as it should with the exception of the AC compressor 'ON' signal via the CAN buss. Blends doors, actuators, fan heat etc all work fine. Outside air temp shows 50 degrees - even after a new unit - no surprise as temp data runs to the HVAC control and then to the PCM via the 'no connect' CAN Buss.,

Any help is appreciated, especially from you folks who work in this arena and surely know more than I. I am learning but wouldn't call myself knowledgeable.

thanks Ralph

 

1st thing you need to do is tell people what your driving, the systems vary with year model and option packages. Be specific, year/trim/cab config/single or dual zone, EATC or manual and yes even engine size.

The internet is great but is not a depository of psychics/mind readers.
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Thanks for the reminder.

2009 F-150 XLT 4x4 Supercab manual HVAC controls in single zone, 5.4 L V8 150K miles w/o issues other than AC

 

There is no procedure for testing out of the truck. Testing is done with the module connected to the truck. I don't have a shop manual for your specific year model truck but here's where you can get one. http://www.helminc.com/helm/product2...109&itemtype=N

Same manual dealer tech's use....or you can access all the same info for 72hrs for $22.00 on this link, https://www.motorcraftservice.com/Purchase/ViewProduct
just use the drop down box to select the time period you want.
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