system voltage output

[RSG]

Curious readings, interested in your opinions...

I have 2 voltage displays, one on the radar detector and one on the Aux Idle Controller...typically they agree within 0.2V. Left for Kentucky Sunday, and they both indicated around 13.1-13.5V and I thought it was a bit low; then on the return late last night, with plenty of electrical loads but hot weather it ran around 12 or 12.1 V for around 200 miles, then edged back up to around 13.3V. Both displays agreed on the values...No problems with dimming or anything that suggested a short in the system. Most of the winter I was seeing 14+V.

My question is, could the charging circuit (alternator/regulator/computer) be manipulating this? My first thought is the alternator is going south; my second thought is a battery has a bad cell.

Thanks!

 

[WD40]

I would do a load test on the battery's first, like at Auto Zone and then have them check out the alternator/regulator. If one of the battery's is bad replace both of them with Motorcraft battery's.
Doug

 

[Tail_Gunner]

First thing to check is the battery cable connections. Make sure they're not tight, clean & not corroded. A bad connection can act like a bad battery.

Check the connections on the back of the alternator too.