motown 71

I have installed an electric fan that draws 16.5 amps. originally I wired it to the fuse box under dash, didn't like this so I ran it right to battery. I am using a 30amp toggle switch so I can run the fan a bit after shut down, but with this direct wiring to battery + cable end my battery gage in dash now is reading a - (neg) when the fun is turned on and the needle is bouncing.....oh the ground is in the engine bay and is good. :confused:
I could just go back to the fuse box I guess.....is there a power source there that is always hot ?
Thanks in advance

Mikeb690

Anything that works when the car is off(brake lights, headlights,tec) is always hot in the fuse panel, make sure you hook it up to the right side so if the fuse blows the fan won't run and won't fry anything. :U

But i would suggest finding another way

71coupe

You should consider installing a relay near the fan. You can pick up a 20amp at radio shack

zwede

You can take power off the alternator. It will easily supply 16A even with the engine off. Do yourself a favor and use an inline fuse though. Mount a relay close to the fan. Pull an always hot wire from the fusebox to your switch, then to the relay. Very little current will go through the switch, just enough to pull the relay. The relay powers the fan with power from the alternator.

weendoggy

Here's how you should wire a fan. Use a relay, it's much safer. :thumbs:
http://www.weendoggy.com/wiring.htm


[Modified by weendoggy, 6:49 AM 4/30/2004]


[Modified by weendoggy, 6:50 AM 4/30/2004]