Recently the voltmeter in my 98 GMC 1500 started reading low, not quite in the warning area but almost. The battery tested fine. Took the alternator out, and it checked out fine. The connections appear to be fine. I haven’t actually had any problems yet other than the consistently low reading, but I want to figure it out before it gives me trouble.
I had someone suggest it might be a bad voltage regulator, and another suggest the gauge is going bad and giving faulty readings.
Thoughts or ideas?
You should check your voltages at the battery with a multimeter. There are many TSB’s about low indicated charging voltages (put out by GM) it is a indicator problem common with many GM products.
Now simply because there is a TSB about the problem this does not mean a good visual inspection, cleaning and as mentioned, verification with a multi meter should not be performed.
Along with Oldschools suggestions you might check to see what the voltage is getting to the fuses in the dash using a meter. If the reading is higher than the dash gauge then the dash gauge most likely has a problem.