All of my gauges will peg full scale when the engine starts to about 2 seconds after it starts, then they will go to ‘zero’ and then they will measure normally, before and after this time frame all is normal. When they return to normal I think that I hear a relay/switch operate. My truck is a F-150, 2001, 4.6L, auto transmission.

I have had this problem only a few times. At first I thought that the alternator was producing an overvoltage, but one of the times that this happened, I turned off the engine within the above time frame. I then turned the key just to ‘on’ without starting the engine. The gauges still went to full scale. I restarted the engine and after the 2 seconds, all was normal again.

I have looked at the wiring diagrams, but could not tell much. Is there a voltage regulator in the gauge cluster? On older models there was one. I did notice that there is a microprocessor in the gauge cluster though, could this be the problem.

Any help would be appreciated.

 

depending on what year the vehicle is ,this could be normal operation of the gauge.and im sure someone will back me up on this.

 

I have mine do that when the battery is low, other then that they work normal. On these computer models you get around 9 volts and they tend to shut different things down, then when the alt gets the volts up it will go to normal.

 

Mine does the same thing. Has done so since day 1

 

It's a symptom of a battery that is losing too much of a charge when the engine is off. The voltage drop is causing the engine management system to lose stored data on fuel trim and other parameters that the system has to try to learn all over again when you start the engine.

If your battery is factory original, it doesn't owe you a thing. Replace it, after verifying that the rest of the charging system is working properly.

 

I had the same problem with my gauges sweeping on start up especially when it was cold. I also had to auto locks lock me out of my truck a couple of times. I brought it in to the dealer and they ended up replacing the battery which cleared up both problems I was having.

 

I replaced the battery this past weekend. It appears to have fixed the problem. I guess with all of the microprocessors and electronics on trucks these days, these devices are more prone to voltage variations.

Thanks for all of the help
‘Git Er Done’