Ok, here's the deal. I did exactly what 90% (or it seems ) of this board has done with the manual fan switch. I tapped in to the green/white ecm wire that is attached to the fan relay next to the radiator.

Well I tested it out with the car running and WHAM!!! the voltage reading drops to 9 volts then back to 13 then back to 9 back to 13... you get the picture.

What is the problem???? When I hit the gas, the voltage stays at 13, but once I come to a stop, it start jumping around.

Can someone lead me to the promise land with this?

Thanks for your help!!!

 

Your alternator isn't turning fast enough at idle to provide enough current to the fan.

 

does sound like a alternator problem, like the voltage regulator.

to rule out the manual switch, maybe just let your fan come on by itself and see if it does the same thing..

if you tapped into the ecm wire on the relay, and then on the othe side of the switch a good body ground.. i should work just like it would when the ecm turns the fan on.

 

i have my fan running with just a hot wire and a ground and it doesnt pull hardly any juice. It sounds like your altanator is going on and off

 

It's normal for that kind of reading especially with a 105 amp alt. When the fan first turns on it can pull almost double the current that it does after it's running. Normally you will see a big dip in the voltage guage when it starts and depending on accessory load(e.g., heater blower, lights etc.)the guage may stay down until the rpm's kick up. That's one of the reasons I pontificate so much about playing around with anything other than the factory design. Running the fan(s) with altered temp switches or with the key on and the like will reduce the life of the alt by more than half and cause premature failure of the fan motors. Cycling them constantly reduces the life of the relays as well. Despite some of the well written articles, from an engineering standpoint the factory setup is the best compromise for all system components and provides the maximum life. I experminted with just about every setup and I have found a 195 stat and a good cooling system with all stock fan control results in the best driveability.