Electrical problem.. I hope one of you Corvette gods can help
 

Hello C3 people,

First off I want to apoligize if a question like this has ever been asked before; however, nothing came up when I searched for it.

Nevertheless, I recently installed a new alternator on my Corvette. I wired it in a 1-wire set up, instead of the 3-wire. (There is also another wire that I was told was a field wire).

Around the same time I did this, I also installed electric fans with an aluminum radiator. The system worked amazing for about 30 minutes, then temperature sensor broke.

I went to my local speed shop and bought another temp sensor. Same thing happened. The black ceramic-type piece on the top of the sensor felt almost like jelly and the electrical connection broke apart from it.

The battery terminals were also extremely hot to the touch. The alternator was the same way. (I have a hunch that the temp sensor is just getting too much power for some reason).

Does anybody know what this could be? I was thinking that maybe I was suppose to ground the field wire from the alternator?

I know it is hard to figure out because I did both the electric fans and the fan install at the same time.

Any response is welcomed. :cheers:


Notes:

The relay for the fans is getting +12V from the starter, and +12V
ignition from the windshield wiper motor.

I am running two sixteen inch fans.

I do not think the main positive battery cable is original.

If you installed the relay for your fans there should be 4 positions.

1. Pin 30, This is usually the main hot.
2. Pin 87, This is usually the applied voltage to the fans.
3. Pin 86, This is the hot side of the control circuit.
4. Pin 85, This is the grounding side of the relay for activation.
I don't know how you have the relay set up but I would take a look. Seems to me that you have excessive current going to the temp sensor for some reason.

First thing to do is take a voltage reading at the battery with the engine running sounds like it might be the new alt.is over charging or over voltage should be around 14.5 volts with engine running.

if you want it to work as designed,
take out that crap 1 wire alternator and put in a good 3 wire.
the 3 wire alternator uses the car wiring to remotely sense the voltage and adjust out put current/voltage as needed. 1- wire does not.

if you keep the 1 wire, disconnect the fans temporarily and deal with one problem at a time. Make sure the alternator is functioning correctly and not back feeding through the ground. once that is solved then check the fans. Most likely the alternator hook up is fine and you are overdrawing the amps on the fan somehow and running a hot to the sensor that is heating the pos terminal of the battery and melting the sensor which is acting as a ground.....


or I could be wrong. Good luck. In the future fix one thing at a time. It will keep you from pulling out your hair

My first impression is that you have the sensor incorrectly wired and you're drawing power thru the sensor. The relay coil wire should begin at the wiper motor (or other switched 12V lead), go to one side of the relay coil, and then the other relay coil lead goes to the sensor-if the sensor is the type that has a single lead and is self grounding. If the Sensor has two leads, the wiring can start at the wiper, and then go to either the relay coil or the sensor, and have the other sensor lead going to ground. Trace the current path. It should start at 12V, and make a loop thru the coil and sensor and then to ground. There should be no other connections to the coil circuit. The power lead from the starter should connect to one contact side of the relay, and the other contact side feeds the fans.