check your fuses and proper ground
Sounds as if the alternator is going out. Have it tested if it is charging on the bench at 12 and a half and below replace
Do you mean charge by the vehicle running....or do you mean take a charge from a Bench charger? if its in the vehicle it could mean that either the battery/battery connection/cables, a faulty ground, or the alternator is defective. If its on a bench charger then the battery has a dead cell or is defective and needs replacing.
In my experience this usually does mean that the alternator is not sending the battery enough charge. Many auto parts stores will bench test your alternator for free, some can even test it while it is still on your car. I recommend getting it tested. They can also test your battery; you would be surprised how fast a battery can go bad. Sometimes you can get a battery that is just a lemon. I hope this is helpful.
It could be that your alternator is no longer putting out enough charge to handle the load of the AC running. Some auto parts stores offer free bench testing of alternators and some can even test it while it is still attached to your car. I would recommend getting it tested. Also, someone may have replaced the alternator in the past with a lower amperage than is required for a vehicle with air conditioning. Hope this is helpful!
In a vehice it is the alternator/generator. On the bench it is a charger.
Car would either have to be running or alternator removed for bench test
Remove it and have it bench tested.
Remove the starter and have it bench tested.
EVILLEONBENCH
Manufacturer defect maybe... go to a reliable shop and have them bench test the alternator...if not working have them replace it... ask to see results of bench test.
Take it to an auto parts store and have them perform a bench test on it.
The voltage regulator (which is inside the alternator) on 97 rodeo's are controlled via the PCM/ECM (Power Control Module/Engine Control Module). A remanufactured alternator for the 97 Rodeo as well as the 97 Passport (Honda), usually will fhow failure while tested in car. On the bench test, however, the alternator tests normal. Aside of the normal problems to be ruled out, ie; alternator belt tension, check for loose connections within and around the alternator, try an original factory alternator. Is this problem affecting your blower motor?