Unsteady Alternator / Voltmeter Instrument Gauge Readings.

Unsteady Alternator / Voltmeter Instrument Gauge Readings.

May 29th, 2013

For anyone who reads this blog entry who might be experiencing an unsteady instrument gauge which is intended to display the voltage output of their vehicle’s alternator, don’t act too hastily in spending alot of money to replace parts that may not need replacing.  If you are chasing what appears to be a ghost in your machine that suddenly caused/causes your alternator output gauge to bounce in what appears as an unrealistic fashion, fear not. 

If you are driving a vehicle with a removable instrument panel, merely remove it gently, gently clean the contacts on the back side of the cluster with a rag and some rubbing alcohol or the likes, and gently re-install the instrument panel (the panel may include the speedometer, tachometer, voltage, fuel, temperature, and oil pressure gauges).  Be careful not to mess up the position of the contacts when cleaning them.  It’s an easy process to remove the cluster and it is well-documented on the internet (just google it to find a step by step process on how to remove the instrument cluster).  Even if you might have a bad voltmeter/alternator gauge, it’s a good gamble to remove and re-install the cluster (at minimal or no cost) before paying (approx. $400) to have the cluster reconditioned which may not be necessary.  And, it’s a good bet that removing and reconnecting the instrument cluster will solve your erratic alternator gauge problem anyhow – as the problem is just as likely as to be an oxidized or loosened contact which occurred over the live of the vehicle to date.

Don’t listen to all the others giving advice over the internet who obviously have not seen this condition reflected in a dashboard mounted voltmeter gauge.  Though they mean well, those others are the folks who likely are posting advice like: to replace the alternator, to replace the battery, to replace the starter, to replace the ground-straps, to clean the fuel injection system, and to start looking at the vehicle’s computer and its connections.   Again, it is unlikely that they have seen such an unrealistic bounce in a voltage gauge, as we have.  For instance, there is no way that a small ‘hunt’ or ‘wander’ in engine idle speed will cause an alternator gauge to bounce as drastically as it can when the contacts are not properly connected as I am describing here.  The others posting advice likely have never seen a alternator gauge instantaneously bounce from mid-span down to battery level and then a moment later bounce back to full charge levels – and do it all so quickly and without reason or without any apparent effect of what would otherwise be an electrical malfunction if the indication was truthful in actuality.  Those others are also likely to be unaware that this bounce in the gauge will appear merely with the key turned to the ‘on’ or ‘run’ position to therefore energize the gauge without the engine running and the alternator gauge still bounces even with a brand new, top-of-the-line battery installed and regardless of no apparent alternator or starter problems (problems which would likely be irrelevant without the engine running).

Don’t end up like many of the others who did not attempt this easy repair and who then spent alot of money trying  to chase this ‘ghost’ out of their machine nor end up like those who have merely resigned to live with the ghost’s high frequency, unrealistic, and erratic bouncing of the voltmeter gauge.  The only folks I know who actually repaired this issue did so as I am telling you here (which is to remove the cluster and then to clean the self-contained contacts on the flexible printed circuit board behind the cluster of gauges).  It’s an easy fix and much easier than it even sounds here and much cheaper than the potentially unnecessary alternative of needlessly replacing perfectly good components. 

Just take your time, and do the removal and cleaning process gently and easily – and remember: this blogs maintains no liability in providing this likely answer to your unsteady alternator gauge problem as described herein.   :)

AVT, P.E.