I wired up a new electric fan from Jegs as well as one of their wiring kits(with thermal switch) last week, it went into my '66 coupe with 200ci:

http://www.jegs.com/i/JEGS/555/10560/10002/-1

http://www.jegs.com/i/Flex-a-lite/400/398/10002/-1

Now the fan worked fine for a couple of days, but then I hit a snag. The fan would come on for a few moments, and then turn off.... then it would sort of jitter on and off. It will shut down and turn off mabe once every 1-2 seconds-very random.

To me, it seems like it would be a relay or breaker overheating. However, the breaker is not clicking-both hot wires are cold to the touch. I pulled the relay apart and nothing looking burned, everything feels cold. If I unplug either the thermal sensor switch or the relay, wait a few moments, then plug it back in the fan will come on for a few seconds (mabe 5-15) and then turn off again. This also makes me believe that something is getting too hot, but there are no other signs of this. All the wires are properly secured, no bad connections are apparent.

I'll also say that I cannot hear the relay clicking when the fan jumps on or offsporadically. If I unplug the thermal switch, I can clearly hear it click on/off....

 

check your grounds again

 

If your getting your main power from the fuse panel, check the fuse holder. The old glass type fuse's like to act like that under load.

 

You might try making a temporary jumper to hook the fan directly to 12 volts to check for proper operation of the fan itself. If the fan works ok when jumpered you can assume the issue is with the relay or breaker.

In any case either of these should be available at a parts store. I know it sucks changing out components on a brand new part, but this should be a reasonably cheap and fast way out of your predicament...

I guess it could be the sending unit, but I am prone to think it is the relay...

 

Good point^^^

I would probably hook the big power wire for this unit straight to the battery side of the solenoid..

 

I am not running from the fuse panel. I hooked it to the hot side of the starter solenoid and mounted a breaker about 8" from there.

 

breaker? I only use fuses. Breakersdo not to work well with vibration. Temporarily change it to a fuse for elimination purposes.

 

I just finished soldering all the connections (before they were all just twisted together) Problem remains. It sounds like a may have heard the breaker a few times. I am going to buy a a fuse now.

 

Did you run it thru a trinary switch by chance? If so, you may need a diode. Anyway, it seems their is a flow across the contacts of some sort (or short) causing it to act this way. If you hear the contacts closing (clicking) in a erratic way, then my money is on the sensor being bad. If the stuff is defective, then why not send it back. Electrical issues show themselfs very quick. They will replace it, usually with no questions. Its worth a phone call, they even may even replace it overnight and tell you to trash the old one.

 

just check for voltage witha multi meter before and after the breaker after it stops