Jim Grant's Tech Tips

’97 Nissan Maxima, Charging Problems

Q: I am having a bit of an aggravating problem on my ‘97 Nissan Maxima. I recently purchased the vehicle for my wife. When I bought the car there had recently been an engine transplant. The guy that sold the car to me was honest by telling me that he was having charging problems. So I thought that it would be a simple repair by changing the alternator. I took the car to get the vehicle tested and the alternator was putting out around 12.5 amps so I changed it just in case thinking this would solve the problem but it did not. I have taken out the aftermarket radio and installed the factory radio back in also thinking this was the problem. I have changed the power antenna because it was broke and may have been the problem. I had the starter rebuilt and also I have purchased the biggest battery that would fit the car, but I still have to boost it off everyday. The ignition coils are also arcing out from the rear bank. I have bought 3 from a junk yard for $90 but the problem still exists. Has anyone ever had this problem before? I looked at the fusible link under the hood on the driver side and the one for the battery does not seem to be damaged but I have not changed it.

- Torin

A: Stop working on the other stuff and focus on your charging problem. You’re replacing a lot of components that have nothing to do with your problem. If the engine was just replaced I’m betting that the wiring to the alternator is damaged or not connected correctly. When you turn the key on does the battery light turn on before the engine is started? It should, if it doesn’t, check fuse number 13 in the passenger compartment fuse block. That 10 amp fuse provides the “it’s time to start charging signal” to the alternator’s voltage regulator when the key is turned on. If the fuse is good and the battery light is still out then that wire has to be checked at the alternator. The electrical signal has to be there with the key on or the alternator, no matter how many you replace, will never start charging. If that checks good then go under the hood to the fusible link box. In that box there will be a 120 amp or 140 amp fuse for the alternator. This fuse must be good along with a little 7.5 amp. That small fuse provides the electricity that the alternator’s voltage regulator needs to know how much charging needs to be done. One other little detail; the alternator on your vehicle has a ground wire which can be tricky. If the ground wire is open/bad or not connected that battery light will turn on with the key but will go out when the engine is started. With an engine that has just been replaced I wouldn’t be surprised if a ground wire or 2 never got reinstalled.