I am having electrical/alternator problems with my '94 Mitsubishi u42t. The alternator is not charging the battery. I took alternator to local shop and had it rebuilt, but the problem isn't fixed. I charged the battery (NAPA #8223) and had it tested. Battery tested good at almost 600 cca's. I've checked the fuses under the dash and they all checked fine. I checked the 30a/40a fuses under the passenger seat and they were fine. The ground wire from the battery to the frame is good along with the ground from the frame to the transmission. After reading different forums I noticed that the battery light in the dash was not lighting when the key was in the on position. I replaced the bulb, but it will still not light. I've got 12v of power to the back of the instrument panel but still no light. If anyone has advice on what I can check next or things I've overlooked it would be greatly aporeciated.
It will be better if you visit your dealer. As they very well know about it's each part and they will certainly solve your problem.
Most probably the reason you have not received any posts to now is that electrical problems are so hard to write about & diagnose. Unless you have knowledge, understanding and a complete diagram to go by, the post by elisagrace would probably be the best way to go. Fred
Never had a Mitsu, but, if it was charging before and now it doesn't after having the alternator rebuilt, well could be something wrong with the alternator itself. Bad regulator would be my guess but, as mentioned, electrical gremlins are hard to diagnose online. I would at least go over the ground connections, disconnect them, some light sanding and retorque them to start with. Hope this helps.
have you checked the voltage at alternator with engine running? if it is somewhere in the range of 13.5-14.5V at the alternator the problem isn't the alternator.
sorry to bring this up from the past but im having issues with my new truck. its a 1991 and when idling at the battery i have 14.46v once i turn on the headlights and fan on it drops to 13.5 and if i leave it outside like that it eventually dies. what am i missing? thanks
The 14.4-Volts is about right when running above idle. And the 13.5-with the headlights on is right. I’m guessing your alternator is producing less Amps than the headlights draw. And your dropping to the point there isn’t enough voltage to energize the coil and it dies. Please go into your profile, and put the information on your truck in your signature line. That way we know what kind of rig we are working on.
Basically it seems ok until I run multiple things IE if I need heater fan wipers and headlights all at once then it's a problem. I want to eventually add a winch so I'm wondering if maybe I need to upgrade my alternator.
Typically the factory alternator was either a 30 or 35-Amp unit depending on what accessories you had. On my S110 Hijet, the alternator happened to be what is know as a mini-Denso. it is very common on skid steers, and small tractors, etc. Most anything running a three or four cylinder engine. And, common on race cars because it is one of the smallest and lightest alternators out there. You can get them in outputs up to 120-Amp. I found a 90-Amp unit on eBay. I had to re-clock it so things lined up, and I went from a three wire to a four wire setup so I could add one wire and have it sense voltage at the battery, instead of at the alternator.; And paralleled the stock cable which runs to the starter and then up to the battery, with a 4-Gauge copper wire. That gave me more than enough wire to handle the 90-amps. Without having to redo the wiring to the starter.
