Quote Originally Posted by 34_40 View Post
No, a stray voltage can still be induced and backfed up the positive side, essentially out of phase even tho' it's not AC current. The fans could potentially pulse feed but I don't fully believe it's happening, This same basic effect happens when you run spark plug wires parrallel to each other. It was so prominent that on ford v8's of the 50's, 60's and 70's one wire on each side of the motor was intentionally placed wrong in the wire seperator to break the voltage spike and false fire the plug!

I was searching if someone here had this experience as I have read about it on one of the forums I frequent.
Well, not to nit pick, but first of all electrons need a path pos too neg. or neg. too pos, no path no go, feed back does not skip over open air. The interruption to ground of the coil that energizes the relay contact opens, no path. Second the spark plug example you bring forth is a totally different circumstance. The plug wire has a high voltage field external to the wire, it rises and collapses as the plug fires, that induces voltage into a wire close to it, this is known as counter EMF all high voltage has that capability.

As to this fan thing being a viable voltage generator ........ Unlikely, it is not going to spin fast enough from the get go. Other items are in play such as . Most circuits in your car are wired in parallel so even if the fan became a power source it would not add voltage. One more and I am all done with this, the fan generator will need to have a greater potential. Greater voltage then the circuit it is wired on, if not it will be ignored by the circuit, the most it could do if it were electrically in the circuit would be a load.

Such as it is, you are or were looking for an intermittent ground. If the car was up on jacks, just sitting the motor out less weight the frame and body sit differently. Maybe it opened up a space,, that caught a little rust, now that you have taken the car out and spun it up a few times, everything in place it has fixed itself. That would not be the first time an electrical circuit got quirky in a machine or car that has sat unused, airplane systems are much worse when the are not flown regularly.