My wrangler overcharges after a few minutes.the altenator tests okay

With engine running.... 'Exactly' how much voltage is it putting out @ battery terminals?... How do you know it's overcharging??

Check the temp sensor under the battery

Stupid 97 is plagued with electrical problems. Take the dash cluster off there are videos of YouTube. Take a small amount of dialect grease and press into the gauge plug under the gauge cluster. Then wipe the excess really good. Dont use a lot it could squish out and short the gauge cluster. Mine did it today it normally drops the oil pressure to 0. I've been meaning to put some dialect grease and haven't gotten around to it.