Best aux fan?

[jdt10768]

thanks so much for that helpful insight jakass619.

So, I put a 20a fuse in slot 3 last night, and it blew. The aux fan is fairly new in past 6 or 9 months. The only other electrical change I have made is installing George Graves' dimmer. How should I start to track down the actual issue?

[jekas619]

hi

unable to answer your question, kindly refer your friends for your answer.

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[jeffnhiscars]

I've traced both the high and low circuit in early and late cars and honestly the only difference between the high and low circuits is the resistor which, if overloaded shorts open and removes the load.

I think the 15a fuse is strictly based on electrical engineering fundamentals that says the fuse should be rated to the design load regardless of what the circuit can handle.... which happens to be 30a.

[FLG]

In which case you are overloading the low speed circuit. Keep a large fire extinguisher within reach and be will to spend a bunch of money to repair the damage (if you catch the fire in time).

A fuse is sized to protect the wires, not the load. If you increase the size of the fuse the wires are then unprotected.

Yes but according to the etm both wires are the same gauge. I've ran it like this for over a year now on super hot track days without issue

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[jlevie]

In which case you are overloading the low speed circuit. Keep a large fire extinguisher within reach and be will to spend a bunch of money to repair the damage (if you catch the fire in time).

A fuse is sized to protect the wires, not the load. If you increase the size of the fuse the wires are then unprotected.

[FLG]

Idk Wtf j wrote there... Lol yes it's on high speed when you press the snow flake. And I used a small nut and bolt to join the wires and then insulated it. My friend needed the resistor

Meant to say "without it, causes it to be on high speed when I hit the snowflake button"

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[jeffnhiscars]

I rarely if ever, never go against Jim. But I have my resistor jumped and never had an issue with wires overheating

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I try not to disagree with anyone but if its Jim I make damn sure I know wtf Im talking about :)

Yes but when I say jumped I mean I have the resistor removed and the wires hooked together without it causing it to be on high speed when I hit the snowflake Hutton

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I generally leave the resistor and use the high side lug as a terminal block for both wires for convenience and it keeps them out of harms way.

Dont you mean to say that with the wires joined it only has high speed when the snowflakes lights up ?

[FLG]

and by 'jumped' - you mean you are using a higher rated fuse in slot 3, yes?

Yes but when I say jumped I mean I have the resistor removed and the wires hooked together without it causing it to be on high speed when I hit the snowflake Hutton

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[jdt10768]

and by 'jumped' - you mean you are using a higher rated fuse in slot 3, yes?

[FLG]

I rarely if ever, never go against Jim. But I have my resistor jumped and never had an issue with wires overheating

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[jeffnhiscars]

Actually Jim, the wiring is .75 for both the high and low speed circuits on the diagrams I have checked which means they will both carry the higher load. I have also not found anything else in those circuits that has been de-rated other than the 15a fuse.

Of course if there is a short or someone has mucked about with the wiring thats something else but if its just a matter of the resister being jumped then then the 15a fuse will keep blowing and a 30a swap by itself should not lead to any problems.

[jdt10768]

thanks, this is stock configuration, so I will replace with a 15a and monitor it

[jlevie]

yes, middle slider was all the way right, top & bottom sliders all the way left.

fuse #3 WAS blown. I replaced it with a 30a fuse, and aux fan starts correctly now.

Is a 30 amp fuse ok? Supposed to be a 15a. I know fuses blow for a reason.

Fuse 3 powers the aux fan in low speed and should be a 15a fuse. Fuse 18 powers the fan in high speed and should be a 30a fuse. If using a stock aux fan in the stock configuration a 15a fuse in position 3 blowing indicates a serious problem with the fan or circuitry. However, if some one has diddled things and is running a non-stock fan or the stock fan at high speed off the low speed relay there is an even more serious problem. The low speed wiring is not sized for a 30a load and the fuse is sized to protect the wiring. Overloading that wiring by increasing the fuse size could result in an engine bay fire.

[jdt10768]

yes, middle slider was all the way right, top & bottom sliders all the way left.

fuse #3 WAS blown. I replaced it with a 30a fuse, and aux fan starts correctly now.

Is a 30 amp fuse ok? Supposed to be a 15a. I know fuses blow for a reason.

[jeffnhiscars]

If your middle vent slider is all the way to the right, which is necessary in almost all e30s to energize the AC, then it is 97.3% likely to be the aux fan resister. Try jumping it and feel free to leave it jumped if it works (again swapping in a 30a fuse for the low speed).