[GumbyJ]

2005 Five Hundred AWD LTD
Couple months now I’m getting power surges system wide. All lights brighten/dim/flicker, HVAC fan flutters and today all the dash gages shut off for about 30 seconds while on the highway.
Alt and bat have tested good. One trouble code for voltage spike but didn’t trip check engine light.
I do have a Chinese head unit but have pulled the fuse and still had same issue.
I’m assuming it’s the voltage regulator in the alt but see what a pain it is to get at and hoping someone has a different idea.

 

[R.S.LOGAN]

Load test both the battery and alternator .

 

[GumbyJ]

Load test both the battery and alternator .

Both test fine

 

[R.S.LOGAN]

I would check battery terminals and ALL grounds . They do suffer from instrument cluster faults also

2005 - 2007 Ford Five Hundred Instrument Cluster Repair

Is your 2005-2007 Ford Five Hundred instrument cluster intermittently dropping out? If so, we can repair your cluster and have it back to you quickly.

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[GumbyJ]

If it were JUST the inturment cluster, that’d be an easy fix. It is system wide - headlights, HVAC, interior lights all surge or flicker. But it’s intermittent