Why would you wire a fan to the wiper motor???
Wiring problems with fan
Thread Starter
Drifting
Joined: Nov 2003
Posts: 1,410
Likes: 0
From: chicago IL
Wiring problems with fan
I have a permacool fan with the temperature control unit (little black box with a stupid a#$ hell little white dial switch) I wired the power up to the yellow wire going into the wiper motor as suggested, now the wipers don't work, and the fan doesn't seem to be turning on either even though I got the engine to 220 (maybe I need to play with the sensor though)
Any advice?
Any advice?
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
Thats alot of voltage to be carried by the wiper wire. If you turn the wipers on high with the fans on you will be over loaded!!!!
It may cause a fire if the fuse doesn't burn out! My fans are powered by the pos. terminal on the back of the alternator.
It may cause a fire if the fuse doesn't burn out! My fans are powered by the pos. terminal on the back of the alternator.
Thread Starter
Drifting
Joined: Nov 2003
Posts: 1,410
Likes: 0
From: chicago IL
Racer
Joined: May 2008
Posts: 323
Likes: 0
From: ********** New York
The fan is controled by a relay it is possible for relays to to feed back which could cause the wiper motor prob.This is why they make diodes not pun or flaming intended most people dont use diodes. I have been wiring cars for over a decade and always take power directly from the steering column harness & fuse it according. This is safest bet to protect your car from electric fires & to insure you get a true 12 V's .
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
I'm guessing whoever suggested the wiper motor wire meant it as a trigger for a relay, and the fan was installed using it as a power supply because it was switched. More than likely the fan drew too much power, the fuse blew, and saved the circuit.
Racer
Joined: May 2008
Posts: 398
Likes: 0
From: Sacramento California
When I installed a derale fan on one of my vehicles, I initially used power straight from the positive battery terminal. This was run through a relay that was connected to a switched ignition source (radio circuit). The radio circuit would engage the relay closing the circuit for the main poower wire, turning the fan on. It takes very little power to operate the relay so there was little additional load on the radio circuit. I also installed a fuse in line with the main power wire to be safe. This worked well untill I installed a fan controller. You can get controllers for electric fans from summitracing.com.
Kelly
Kelly
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Racer
Joined: May 2008
Posts: 323
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From: ********** New York
to be honest I havent looked at my column harnessin my 69 but for as far back as I can remember all GM at the colum have a RED 10 awg cable for 12V and a PINK 10 awg for ignition-aka turn on these are the safest wires to use.........
Thread Starter
Drifting
Joined: Nov 2003
Posts: 1,410
Likes: 0
From: chicago IL
Thanks for all the advice guys, I just remember a bunch of threads about power sources and a ton of people said the wiper motor was a good switched source (on at ignition), I think I may have confused it with sources for choke wiring, I'll look into hooking it up to the alternator as this will be easiest for me to do, climbing under the steering column is way too 
especially when you're 6'4"
especially when you're 6'4"
Burning Brakes
Joined: Feb 2000
Posts: 1,246
Likes: 1
The switched source is only used for the relay, not to provide power to the fan itself. The relay will control the fan switching. This is done with a temp sender that makes a connection to ground when it's switched. This then switches the relay. If the relay's switching side is powered by a 12V from a switched source (in your case that would be the wiper motor) the fan will only run w/ the key on. Otherwise, when the engine is hot the fan will keep running until the coolant has sufficiently cooled.
Anyway, there should be an empty ign switched terminal on your fusebox, use that instead of hacking up oem wiring.
Anyway, there should be an empty ign switched terminal on your fusebox, use that instead of hacking up oem wiring.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
The switched source is only used for the relay, not to provide power to the fan itself. The relay will control the fan switching. This is done with a temp sender that makes a connection to ground when it's switched. This then switches the relay. If the relay's switching side is powered by a 12V from a switched source (in your case that would be the wiper motor) the fan will only run w/ the key on. Otherwise, when the engine is hot the fan will keep running until the coolant has sufficiently cooled.
Anyway, there should be an empty ign switched terminal on your fusebox, use that instead of hacking up oem wiring.
Anyway, there should be an empty ign switched terminal on your fusebox, use that instead of hacking up oem wiring.
There should also be an empty ACC switched terminal as well, and will work fine too IF the IGN terminal is used.