Hi Everyone,

I have a 2004 F150 that has been sitting for 2 years. (My brother passed away and it sat for a lot of stupid reasons not worth getting into). I am currently trying to fix a couple of issues with it that I need some advice on.

I took the truck to a mechanic to get it scanned because I don't know how to use my late brother's scan tool. He said he was unable to pinpoint what was wrong (the truck won't go over 60kph (40mph) and won't shift properly) because there is an electrical issue interfering with the scan. Here is what I know about what was previously wrong with the truck:

When driving it would suddenly experience and complete and total electrical cutout. All gauges would stop working. The radio, the fan, windows, lights, everything. It would just cut out. The truck would keep running but nothing electrical would work. If you hit the top of the dash near the centre everything would come back on again. So...broken wire in the dash somewhere? or a bad ground? Could this be the problem with trying to scan the truck? Where would you start if it was your truck?

Getting rid of the truck is not an option. My son wants it so I will get it fixed come hell or high water. Any help anyone can offer me would be greatly appreciated.

Thank you,
Mary

 

My money is on a bad ignition switch.

 

Thank you Alloro. Can I ask what makes you think of the ignition switch? Wouldn't I be having problems starting the truck or keeping it running if it was the ignition switch?

 

The ignition switch has multiple internal switch segments that operate in tandem mechanically. For example, there is one layer that provides power in the RUN & START positions and another that is hot in the ACCY & RUN positions. The first is the portion that provides the power necessary for the engine to run, the second is what enables all of the accessories that are supposed to work when the ignition switch is in the ACCY/RUN positions.

While the actual switch itself may be the issue, that circuit goes through a fuse (F1) then to the instrument cluster which has all the circuitry (relays, etc) that enables all of the accessories. An intermittent connection anywhere in that path would produce the same symptom (no accessories) if the cluster lost this power feed.

I've seen multiple reports of cracked solder joints on the instrument cluster connectors that have caused intermittent operation. I'd probably give this a higher probability than of a faulty ignition switch since the shock of hitting the top of the dash is more likely to affect the cluster than the switch.

 

Thank you, that makes a lot of sense.

 

That way you could pin point where you are not losing 12vdc
Most likely cluster but you must rule out a loose connection to dash .