View Full Version : Electric fan override for a/c
I have a electric fan powered by the factory wiring. Some folks chimed in saying the factory electric fan is a pulse width modulated signal and would eventually damage my aftermarket electric fan so I want to put the thermostat controller on that came with the fan and wire it directly to the battery......
I need to find the instructions to see if it mentions where, on the car, to tap in to auto kick on the fan when the a/c is turned on. But I wanted to ask here just in case it doesnt mention it or cant find them.
I search a little and didnt find it. If someone knows of a post please link to it here.
Thanks all.
larryo340
09-19-2007, 12:25 PM
You might be able to tap into the A/C clutch turn-on and wire it to trigger a relay. It should have only a little draw on the A/C clutch.
Anybody else know?
Breadfan
09-19-2007, 12:32 PM
You might be able to tap into the A/C clutch turn-on and wire it to trigger a relay. It should have only a little draw on the A/C clutch.
Anybody else know?
That's what I was thinking, unless there's another signal wire you can use.
An alternative is to put in a manual override switch and you can turn it on manually when you put the A/C on and also have manual override for hot days, track days, or traffic days or any time you want the fan on.
Todd I put in a over ride switch to the stock one using a relay on the GM.
larryo340
09-19-2007, 06:59 PM
That's what I was thinking, unless there's another signal wire you can use.
An alternative is to put in a manual override switch and you can turn it on manually when you put the A/C on and also have manual override for hot days, track days, or traffic days or any time you want the fan on.
I like the addition of having a manual overide :)
Tom Doan
09-21-2007, 05:04 AM
I have used the stock Bosch controller to run a Derel duel fan set up with no problems before. Now I am running a single Cobra fan with one relay coming off the AC clutch wire and one relay running off a dash switch. This has proved to be problematic, the Cobra fan draws lots of current and I have had to heavy up the ground to a braided wire then the main has been upped to 10 gauge and I carry spare relays at all times, they last 6 months. Tom
I like the manual override as well. As long as it isnt manual only.
I still havent looked for the instructions that came with the fan but will be doing that today.
Breadfan
09-23-2007, 08:17 PM
Sounds like Tom has a good solution but may need to find a higher amp relay, what are the specs on the one you're using?
Tom Doan
09-24-2007, 05:20 AM
I'm using the standard little black Bosch 30/40 amp relays with 5 male plugs on the bottom.
Thats what I used. No problems.
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