Where is the ground for the cooling fans? I tried back-searching from the fans, but I can't find where they actually ground at.

I'm having a problem when the fans kick on. They seem to draw an extreme amount of power. At night, the lights dim considerabley when the fans come on. The rpm drops momentarily, as well.

I had the alternator checked, and its good. Putting out more than 100 amps under load. And I believe it was a steady 14 volts. The battery is a cheap-o, but it tested ok, and it seems more than willing to start the car. I checked the grounds at the battery, and the body, and on the engine. I also added a second ground strap from the battery direct to the engine. 0 resistance from the negative post to any point on the engine, or engine bay.

Could it be that the battery doesn't have enough reserve power?
Or am I right for suspecting the fan ground?

 

Some dimming would be expected if the AC is on; which engages compressor, AC clutch, and cooling fans. I would suggest getting a battery voltage monitor (walmart $15) and watch the DC voltage when fans come on. If voltage is being pulled down below 10V, then something may be going on w/ the fans, perhaps dragging. Other possibility is internal short in AC compressor clutch causing high clutch coil current draw.

Lack of ground to fans should not cause lights to dim, but could cause fans to fail to run or run slowly.

good luck

 

I was assuming that the ground was not as good as it should be, with usually causes an excessive power draw.

 

A weak or loose ground causes high resistance and less current draw. A short circuit to ground can cause a high draw but should cause the fuse on the affected circuit to blow immediately.

Fans that are dragging (horrible screeching sound) might draw more current, but I've had this happen and it did not blow the fuse.

Note, all Acura and Hondas have a power conservation circuit that disables the alternator when battery is fully charged and load is low. This causes the lights to dim when this happens. The voltage monitor I suggested would show when voltage is dropping and should coincide w/ dimming.

good luck

 

^ As always, good info.