Had the dash out t replace the heater core leaking. Reinstalled and things were good. Drove it for a few days and then parked for one week.

Now truck will not crank over at all. Battery is checked out good. The red security light comes on but flashes. All other gauges come on except for transmission selection lights (that shows wht gear it is in)

Cruise control not working, getting CF! Error on trailer brake module.

anyone got suggestions ? Thank in advance

 

may be a theft issue. try a positive battery disconnect. if no change, have the codes read and record them. clear the codes. see if it cranks. if not post the codes that reset.

 

I've found on some forums folks use the phrase "will not crank over" to mean that the starter motor spins the engine but the engine fails to fire. Mustangwally, when you say "will not crank over" do you mean the starter does not spin the engine or do you mean the engine spins but never starts? If you mean the starter does not spin the engine, do you hear any noise (single relay click, no relay click, etc.)? If you turn the headlights on, then try to start the truck, do you see any change in the headlights when the starter should be engaged (flicker, dimming, no change)? Do you have a scan tool that can check for diagnostic codes? Have you confirmed the battery cables are clean and tight at the battery? You mention the flashing Security light. Is that flashing when you are trying to start the truck, flashing all the time, or flashing when the key is removed? Is it a rapid flash, or about once per second?

-Rod