my fan thermostat controller keeps blowing the fuse

[rockyracoon]

as I described in my previous post the fuse on my controller keeps blowin.my fan is a sn 95,the controller is a hayden adjustable,the fuse that keeps blowing is inline on the wire that goes to the fan from the controller.If I hook it up on low speed the fuse is fine but on high it blows the 25 amp fuse.I tried a 30 and it blows but not right away,soetimes it will endure a few cycles.the controller has a relay that plugs into it,but I think that is for the A/C. could I use a relay in place of the inline fuse,keeping in mind that the fuse is on the outbound side of the controller.I thought a relay is nothing more than a swich that allows lighter gauge wire to be used on the switch side.I mean I could see how a relay would be helpful in my situation if I simply was controlling my fan from a switch inside the cab,but I dont want to have to remember to turn on a toggle when the car gets up to temperature.has anyone else used a relay in conjunction with a fan controller.I just dont see where that would be helpful.it seems to me that if my computer was controlling the fan(as the newer stangs do) since it would go from low speed then to high when the computer deemed it necessary the amps wouldnt go as high like mine does starting up on high giving that initial 3 or 4 second spike in amps as opposed to starting up on low.any suggestions greatly appreciated.

 

[86bluecobra]

if you are popping fuses usally i would suspect a short somewhere. And you should always wire off a relay.

 

[HISSIN50]

Parts of your thinking are right on. The factory does try to ramp the fan up by using low speed before high. When I use my manual switches (SN95 fan) I do the same - I run low for 10 seconds and shut it down and switch high on.

A relay with a controller is a great idea if the controller doesnt come with a relay. What is the on-board rating of the controller? You might simply be overwhelming it. In any case, an auxillary relay helps unburden the controller.
For the high speed of a SN fan, I dont think your fuse is rated high enough (they can reportedly draw quite a bit of juice at start up). I know high really loads up compared to low speed.

Another thing to consider is the high speed fan terminal. Is yours charred or burned at all? Some of the motors were a recall item.

The easy way to go would be with one of Baskin's controllers www.DcControl.com .

Good luck.

 

[bsedwebt70-5.0]

mine did the same thing - I put a 40 amp fuse in it that I found at Advance auto parts - I have since switched to a 40amp circuit breaker in line - never a problem with the 40amp fuse or breaker yet.