[FC] Problem after installing High Volume Blower Motor

[Joel McGregor]

I thought it kept running not ran for a while and stopped.  Did I miss something?
You don't have to respectfully disagree with me.  You can just tell me I'm an idiot if need be.  No problem.
Cooking a diode with reverse polarity has to do with it's breakdown voltage and not it's current capacity.  I was wrongly assuming it would be connected in series but it's connected in parallel.  I just looked up how the diode is connected inside the relay and you are correct.  Connecting the relay coil wires up backwards would cook that diode.
Joel McGregor

Subject: Re: [FC] Problem after installing High Volume Blower Motor

I have to respectfully disagree Joel.  The fan spinning down absent of power is what turns the fan motor into a generator for a second or two.  That is the backfeeding that is harmlessly routed to ground through a correctly placed diode.  The diode is just tapped into the hot wire and the other end is grounded.  The diode is not in series on the hot wire ever.  The backfeed current is minimal - hence the small diode.  I recommended a particular 3amp diode because they are easy to work with without a magnifying glass and tweezers - but are still way overkill amp wise.

Saying it doesn't matter which way a diode is hooked up is like saying it doesn't matter what end of the gun you are on.  I prefer to be on the stock end... not the barrel.

There are so many variables that even guys with the exact same fan wiring may not experience the same run on.  How "tight" is the fan motor, the weight of the fan (flywheel effect)... type of ignition system... resistor or not inline feeding the ignition.  I bet Andrew's van doesn't run 2 seconds after he turns the switch.  Some peoples may run a half second or full second and never even notice it.