D@mn electrical gremlins!!!

Hi all, Blair here. I have an 89 XJ Laredo with the 4.0 and the B/A 10 5 speed. My question is, Until a couple days ago, my voltage gauge read around 14, now it starts there, but slowly works it's way down to just above 9 and hold there. I don't know if it's a battery or my alt? Any ideas? Thanx! :gonnablow

If the vehicle still starts with the voltmeter reading 9v, then it's probably a bad gauge or wiring. If you have access to a multimeter, an easy check is to check the battery voltage with the engine idleing; it should read about 13v-14v. Take the reading across the battery posts, observing correct polarity.

Checked voltage while idling, between 14.0 and 14.5, with the engine off 12.0 and 12.5. It seems to drain while driving, what the heck could that be?

OK those readings are normal, so your alternator and battery are apparently good. There are several ground circuits on an 89. Check the one under the dash to the left of the steering column; make sure it's clean and tight. It grounds the dash gauge cluster.

Also check the wires that ground to the engine block (passenger side), that are near the dipstick tube.

How are the headlights when it's running at night? If they're bright, and do not vary greatly when the engine is revved, I think you simply have a faulty voltmeter gauge.

Welcome to the forum.

Before you do anything else, check and clean the battery terminals. Those replacement bolt on terminals are notoriously bad for corrosion and loose bolts. Also, if your battery has the removable caps, check the electrolyte levels. Good luck!

And make sure your belt is tight.

I found the problem in the wire just beyond the clamp, almost solid green inside the sleeve. A little snip, a shot of electical cleaner and a new clamp and the gremlin has left. (For now!!!) :repair: