Intermitent Dash Power
 

I have only been a member for a week, and already have a new problem.
While driving on a good road, all my dash gauges acted up. first, all of the orange warning lights came on, then the radio went off, and all of the instrument cluster went dead. Truck kept running fine. Few miles later, radio came back on. I hit a bump, and all the orange warning lights flashed on for a second, then off. 30 miles later all instruments came back to normal, even my cruise control resume button responded as tho it had never been off. Next day every thing works normal. Any suggestions will be appreciated.

Any time you have an electrical problem of any kind, start with the basics.

The battery is the beginning and end of your electrical system. Visually check the negative and positive terminal for corrosion, and make sure they're tight.

Once you've done that, take the vehicle to your place of choice (autozone is mine) and have them check the alternator and battery with their tools. They'll do this for free in the parking lot.

If it all comes back O.K. then the next thing to do is start looking at fuses. Use a multimeter or test light (preferably the former) and check each one using the little tabs on the tops of them. Turn the key on and start probing around on each side of the fuse. Some fuses you may get voltage, others you may get none. The important thing to look for is that each side is the same. For example, +12 on one side, +12 on the other. That fuse is fine, check another. Ground on one side, ground on the other, still ok, check another. +12 on one side, ground on the other, red flag. If you find such a fuse, replace it with the appropriate amp rating (7.5 with a 7.5, 20 with a 20, 5 with a 5, etc).

If none of that yields anything, the next thing I would check is a faulty ground. It's possible that both the radio and the instrument cluster share circuitry somewhere, likely on the ground side. When you hit a bump as you describe, the ground can come loose and cause your symptoms. The reason being is that voltage is going any way it can to get back to ground, which causes some really strange things to happen.

To start with that, pull the radio and instrument cluster and use some contact cleaner on all their connections, then plug them back in, making sure everything is nice and secure. If the problem remains, find some wiring diagrams for your 2008. I'm sure RonD, another user on here whom you may have seen, will know where to get them from.


EDIT: Back to the battery for a moment. If you have a multimeter, measure resistance between the top of the battery post and the terminal itself. You want it to be at zero ohms or as close as possible. Believe it or not, but this can case issues.

+1 to what TheArcticWolf1911 said


You have what is probably the most difficult issue to track down in a vehicle, intermittent electrical problem.

You have a full electronic dash(HEC, hybrid electronic control) in an '08, it has its own microprocessor built-in.
Which is good and bad, in anything, lol.

There are tests you can do, Google: ford hec test mode
This will reset trip ODO
Basically you push in the ODO reset button and hold it in, turn on the key and wait for TEST to show up in the ODO display
Release ODO button, then press it one time to go to the next test, I think there are 16 tests it can do.
Turning key off will end the test and dash will be back to normal next time key is turned on.

Fuses #1, #3, #5 in the engine fuse box supply the power to the cab systems, so check those for snug fit and clean contacts

Since engine was fine I would focus more on the SJB(smart junction box), it is the new name for the fuse box in the cab, behind passenger side kick panel. the 3 fuses above feed the SJB power.
Loose fuse or wire there can cause odd power outages.
I would turn on the key and then tap(hit) around the panel to see if you can get a repeat.

thanks for the reply. I was not aware that the fuses could be checked while in place. Everything is working fine now, so its hard to find fault.