They are brand new alt and big battery, and had them both rechecked, it's like I have a bad ground somewhere, just can't find the damn thing. I'm thinking its in the light switch. Went to bone yard and didnt find anything close.

Did the external meter show anything close to 14 volts charging when you have had it on? When the temperature under the hood is higher my 98 shows a lower voltage. So starting the engine these cold 45 and 50 degree mornings here in the W. Ohio area should give a reading at the highest because the alternator is sensing a colder ambient under the hood until the air there warms up.

I looked at the 98's factory manual to see how the internal gauge is wired. It shows that it gets power for the cluster from the PCM fuse and the other end terminates in the PCM, but it doesn't show that as being grounded by the PCM. I'll check my 93 manual later to see if that year was wired differently.

You have already replaced the PCM, so that's likely not a factor.