what would cause my tach and speedo to be erratic after changing batteries

by joe

My truck stalled during idle took alternator off had it tested....tested good but batteries were bad I replaced them with new.

I started truck and it runs fine but now tach and speedometer are erratic and my truck is now goverend at 65 when it wasn't before I changed batteries......any ideas what would cause that!!!

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Aug 08, 2011
Check your whole electrical system
by: Vicki Simons

Hello, Joe,

I'm sorry you're experiencing problems with your tachometer and speedometer in your truck.

My husband Mike once had a problem with some of the instrumentation on the dash of his truck that was completely unrelated to the batteries in his truck but was very aggravating to diagnose.

The problem Mike encountered was brought on by plugging a Tornado Fan
in the 12-volt cigarette lighter power outlet in the television-sized compartment of his truck. When the Tornado Fan was in the outlet and working, it messed up his truck's electrical system. We acknowledge that there may have been an electrical problem associated with that outlet.

I submit this comment only as a means of asking if you're absolutely sure that it is battery-related. You may want to check your whole electrical system to make sure that there aren't other contributing electrical issues.

Troubleshooting the problem can be time-consuming, but in the end it will be worth it. If we had done troubleshooting of one of our inverters
we would probably not have purchased another one when we determined afterward that a burned out fuse was responsible for the first one not working correctly after a while.

I hope this helps.

We wish you safe travels and lots of money saving opportunities on the road.

Best regards,
Vicki Simons


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