Where's The Fuse?

[Guest Phil_neast]

Help :-)

 

The alternator is not charging on my S7 with a dolomite loom. I've had the alternator checked and its ok, which leads me to believe there maybe a fuse somewhere I am missing? I have checked the fuse box and they are all ok. The engine is a pinto.

 

Is there an inline fuse somewhere that could have blown and I have missed it? We have been sorting out the loom, so we could have shorted and blown a fuse but where might it be........

 

Thanks

Phil.

[spg]

Phil

 

Don't think there is a fuse in the charging circuit. Just one the the switch ignition circuit for the ignition / charging light.

 

HTH

 

Steve

[Guest MarkB]

have you checked the battery light works, if the bulb has gone it will not charge

[Guest Phil_neast]

The charge light on the dashboard comes on and stays on. The battery seems to have a constant 12.4 volts in when checked, I am wondering if it is charging but this is down to a poor earth?

 

Phil.

[Guest Deathbystan]

Rather than checking the voltage at the battery, check it direct from the back of the alternator (the main lead). This will give you a true reading of alternator output. If you get charge voltage there, then you having a wiring fault. If it reads battery voltage then check your earth ( connect volt meter between alternator body and negative battery, should be <0.5v). If earth reads normal, then it's definetly the alternator at fault.

[Guest Phil_neast]

Thanks for the help, i'll try all of those

[nigelt]

You could try using a bigger wattage bulb for the charge light as a test. I found that when I first put it all together the battery charge light would not provide enough energy to excite the alternator. If I used a headlamp bulb it started charging. Now I'm not suggesting you use a headlamp bulb all the time, but this will indicate a problem in that area of the wiring. It maybe a bad connection on the alternator (Enough for the charge light to light up but not enough to generate the excite current in the Alternator). This would also be a problem if the charge light is an LED.

 

Once I had cleaned all the connections and got a good grounding the alternator worked fine with the normal bulb.

 

Nige

[Guest Phil_neast]

Thanks Nige, the indicator bulb is indeed an LED so that may help point me in the right direction. I am going to double check the wiring tonight and particularly the earth as this seems to be the route of all evil in my car :-)

 

Phil.

[fry61]

There is almost nil current flowing to excite the alternator when using LED ; put a standard 5/6 watt filament lamp in parallel with the LED & see what happens. A resistor should have been provided with LED warning lamps to provide the required voltage to power up the alternator. IMHO a lamp is better as gives two indications of charging.

[Guest Phil_neast]

Hi, I've installed a pre wired bar that has indicator lights and high beam all in the same set of lights. It was all pre wired so had assumed any kind of resistor etc would have been in the pre wired bit. I'm going to have a concerted look at it all tonight and try some of the options suggested.

 

Thanks

Phil.