Volt gauge reading high after warming up

[TonyB]

Hello,

My volt gauge on my 1992 Ranger moves 14v-15v range (still in normal range)on the gauge when it has been running for awhile (warmed up). Is this ok ? Does it indicate a problem with the charging system ? If so what should I check ? Thanks for any help.

Tony

[MAKG]

It's a LITTLE high. Get a more accurate measurement with a real voltmeter.

Also, see if the voltage changes with RPM. It shouldn't above off-idle (though it might go down a bit at idle).

If it really is overcharging, that's a failed voltage regulator. It's integral to the alternator on these trucks, so you just replace the alternator.

14.5V is considered normal. But if there is any doubt, remove the alternator and take it to your favorite auto parts store for bench testing.

Note you can also test the rectifier by measuring AC voltage -- this should be negligible on a properly rectified charging system. Note that bad rectifiers usually undercharge, but they don't necessarily have to. The rectifier is also integral to the alternator on RBVs.