bad ground?

[Ken B.]

I installed a electric fan in my 75 to help aide in cooling. I first hooked it up to a source that only worked when the car was running, but when i shut the ignition off the car ran until the fan stopped turning. I then hooked it into the fuse box(heater fuse) the car shuts off but i keep losing my radio memory(digial after market radio) Any ideas why? My guess is a ground issue but electrical is not one of my strong points. Thanks
ken

[John H.]

Re: bad ground?

Ken -

Aftermarket electric fans connected to an ignition circuit need a diode in the feed circuit to prevent backfeed from the fan. Your aftermarket digital radio needs a full-time battery feed (hot all the time) to keep the memory "alive"; many have a wire separate from the main radio feed just for that purpose.

[Ken B.]

Re: bad ground?

Ken -

Aftermarket electric fans connected to an ignition circuit need a diode in the feed circuit to prevent backfeed from the fan. Your aftermarket digital radio needs a full-time battery feed (hot all the time) to keep the memory "alive"; many have a wire separate from the main radio feed just for that purpose.

John..The radio has the wire for the memory connected. I have it connected to one of the extra battery terminals on the fuse box.