I have a 93 dodge ram that I recently replaced the water pump and the original pump the fan was seized and rusted into the pump and I was unable to even get the fan apart. So I decided to get a 16" Electric Radiator Cooling Fan 12V 2750cfm. I ran the fan to a wire tap to the inside fuse panel and tapped into the radio fuse. I started the truck up everything worked fine, the fan spun, everything was working. So this morning I go back out to start it up and its dead. No crank, nothing. I checked the battery with a multimeter and it red about 12.45V. Despite the voltage being normal in my opinion I notice the interior light was not on like it should be if the door is opened. So I jumped the truck and it started right up first try. I then found that the fan must have blown the 10amp fuses from the fuse tap for the radio so I I swapped in 20amp fuses into the tap and they held strong. I got about 100 yards down the road and the truck completely shut off and was electrically dead. I checked the 20amp fuses they were fine. I got another jump and it started right back up.

Does this mean my battery cannot handle the amp draw from this fan? Could it be that I cannot use a fuse tap off of the radio?
What would cause the truck to act dead but still hold a 12.45V charge?

 

did you wire i relay into the fan? if not id bet thats y...they tend to draw amperage

 

not saying its your problem,but i have a 93 d150 that just died and shut off. mine was a fuseble link on top of the driver side inner wheel well,it was the small red or orange one on the end of the wire mold,coming off the battery pos. i lost all gauges,key switch did nothing.
hope this helps in some way. good luck

 

i'm wondering where the fan is getting its power from? if it is drawing its power from the same fuse as the radio that may be your problem. an electric fan should almost be on its own circuit with how much of a an initial draw there is.

 

Wire the fan directly to the battery w/inline fuse and you should be fine. Use shrink-tube on your connections to seal the moisture out as well. Those wire taps are garbage to start with, nevermind trying to power an electric fan motor off of another circuit.

 

When you install an electric fan you need a relay and a temperature switch. Ground one lead (neg) of the fan and one side of the temperature switch. The other lead of the switch grounds the relays control coil. The relay coil should get its input/control power from a 5 amp fused circuit that has power only when the ignition switch is in the run position. The relays input to the load contacts should come from the battery thru a 30 amp fuse. The fan gets its power from the output of the relays load contacts. I don't know what amperage your alternator is but an electric fan usually needs at least a 70 amp alternator. Do you have A/C?

 

It's not my intention to be rude or mean, but you sure did a big mess there. Why attaching an electric cooling fan for the engine with just the power intended for the radio? Thank God you didn't catch up on fire along with your truck.

I'd suggest you to install a relay just as SEAL said. You can still get power from the radio circuit but I'd strongly recommend you to get ignition key signal from another wire and that signal must go to that relay SEAL is talking about, not to the fan directly. Also take the advice on the temperature sensor, for the cooling fans are not designed to be constantly working due to all the amperage and the heat that may produce in the wiring on extended periods of use.

Make sure to install fuses and all that, because all of them cooling fans sure draw a bunch of amperes and can heat up the wires. I'm sure you don't want to lose your investment, so follow our advice.