I have a 1998 grand marquis bought new battery and new
alternator yet when car is on it only charge at 12.5 and
when it is off when the key in on the battery symbol
The wiring to the alternator would need to be checked. Make sure there is not a broken wire at the plugin.
Has brand new pigtail Rowefast , when I put the car in on position the battery doesn't show on the dash but once I start the car and put a multi meter it shows 12.5 but if I accelerate it just goes up to 13.5 and then it shows battery on dash, changed alternator twice , new belt , new battery. Can a ground be causing that?
The alternator is grounded when it's bolted to the mount, and the other grounds would be good since the car is starting. When you took the other alternator off was it tested? It sure sounds like it is still a bad alternator.
Yes, there was a new pigtail put on it the colors are yellow , white and light green , the yellow and green are connected to the yellow and green from the car but the white one from the pigtail isn't would you know where that goes there is no spot for that one but the white wire is also throwing 13 volts any ideas?
It looks like there are 3 wires that need to be hooked up. The yellow and green one sound like they are connected to the correct wires, the white wire is what needs to get connected somewhere, but I'm am not sure where. Look for another white wire, check up the wiring harness to see if there is an open wire. You may have to search on line for a wiring diagram.
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