Hello everyone and tech gurus, on my recently purchased 2005 F150 XLT sometimes upon start up the speedo and tach needles dip just under the usual rest point 0 marks and vibrate like they are having a nervous fit.
Once you leave it alone at idle or rev it slightly they will start to work as they normally should and it does not happen again unless you turn off the ignition.
The tach needle never goes fully to the 0 mark in the usual way when you key off the ignition normally but stays about 2mms above the 0 mark so thats another issue that might be related to this problem.
The other four smaller gauges for oil,temp fuel and charging output work normally so this is only effecting the two large ones.
The LCD display for odometer, compass and outside temp works as it should so thats also good.
I have a brushed aluminum faceplate to put onto the gauge faceplate to give them the individual look, so if anyone has a known fix for this "nervous needle" issue I will appreciate your input on how to solve it when I go into the cluster without having to start from scratch on where to look for this weird problem.
I hope its not something like a CPU acting up that drives the two large gauges, does anyone have any ideas on this??

 

most likely its your battery(might be time to replace), when my battery died my dash needles would chatter.

 

You would think so, but as a simple test I've repeatedly started and turned off the truck to see if the battery is loosing its cold cranking capacity.
Nope, it doesnt seem to fail the repeated starting test, so while its a possibility at the present moment the battery seems to be acceptable.
Maybe I need to do a high amp drain test to see if any cells are getting weak.
This is just plain weird and still does not explain why the tach needle does not sit to 0 when the ignition is off.

 

Weak battery or poor connections. The batt voltage is dropping to low during crank and making the modules go goofy. you may also lose your clock and send radio into reboot. Best test the batt the proper way.