[DMCForum] Re: cooling fan follow-up

["checksix3" <jetjock11@xxxxxxxx>]

--- In DMCForum@xxxxxxxxxxxxxxx, Martin Gutkowski <martin@xxxx> wrote:
> Can't be bothered with the explanation but all the crrectly 
functioning fans I've measured draw around 8 amps each. These fuses 
are not quick-blow, but anti-surge, that is they require heat to 
pop.< 

Now Martin, don't be hiding information. ;) 

I know what you're saying though. After his "sincere" response I 
wrote up a long explanation for Eric and I may even post it at some 
point. The bottom line is anything that "melts" (his original post is 
confusing at best) is indicative of insufficent ampacity, either a 
design error in the device that failed or a problem downstream of it. 

I also pointed out the question of fuse type: MDL slo-blow, ect. As 
you know, this particular circuit is an inductive load and will have 
inrush until the back-EMF builds, as with any DC shunt wound motor.
I've looked at John's stuff and I feel it's a tad weak is some areas. 
It'll do the job but must be watched. (After all, Eric's failed in 
some "mysterious" manner).

My point was that, based on his somewhat confusing (no pun intended) 
post, reducing the fuse rating won't solve his problem. He may well 
end up with nusiance openings of the lower rated fuses. Until he 
determines the current (again no pun inteneded) load on the system he 
won't know if it's components have sufficent ampacity to do the job. 
And if said load is excessive the cause must be tracked down.

I think Eric was talking about the fan fix module, not the fan fail 
but I'm pleased to see you're now repairing fan fail modules. I've 
never understood why people remove them and go with all sorts of band-
aid approaches. After determining the root cause failure mode and 
correcting it the stock fan fail module is 100% reliable and then 
some. You should see the rig I use to test them: electronic load 
(running a remote PC based test program) coupled to an 80 amp CC 
supply and mutlipoint thermocouples. It tests them under load  and 
total cycle conditions they'd never see in the car. I always had a 
good laugh when "knowledgable" people would point out in horror that 
I was still using the "dreaded blue module". 

Good call on the dual fan relays, it should've been done that way 
from the beginning. Same with John's "headlight switch bypass kit". 
It's a needed gadget, although anyone who didn't sleep through high 
school science class could do the same thing at the local auto parts 
store with his eyes closed. John's stuff serves a purpose but lets 
face it, it's aimed squarely at the "electricty for dummies" market. 
It could be worse though, at least he charges a fair price.

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