how to hotwire the fan?

[Renthorin]

When I get home from running about the fan shuts off when I turn off the car - no surprise there.

I would like to leave the car outside the garage for a while to cool down with the hood up and I thought it might cool better if the fan were running for 10 minutes or so.

How can I make the fan run without the car running?

I have an ashtray switch panel but not sure the switches would like that kind of power flowing through them.

Can I make a wire with alligator clips on each end. One on the battery and one to.......where on the fan?

 

[rpk250]

I bought a kit from Caspers electronics (I think) that installs in between the connectors behind the AC compressor that includes a switch that I mounted underhood which you can manually turn on and off the fan anytime you want. I turn the fan on in the staging lanes at the drag strip to get the engine cooled down before a run.

 

[83ttypecooled]

Hi,
Our cars have a relay which will run the fan if needed when the the car is off. The relay is often troublesome, so watch out. It is located on the driver's side, lots larger than the rest. Good luck with this!

 

[87NAT]

If the car is hot the fans should run for a while then shut off by themself.

If you want to manually kick them on...Splice a wire into the green wire on the intake located right below the tv/throttle linkage...its the one with a plug hooked onto a sensor that runs into the intake for the fans to kick on after a certain temp(well over 200 I think). Run this wire to your ashtray switch and the hook up a ground to the other side of the switch.

The sensor on the intake grounds the wire after a certain temp and that kicks the fans on...your just doing it manually whenever you want.

HTH

 

[TurboMonte 2]

When I get home from running about the fan shuts off when I turn off the car - no surprise here.

Actually, it is somewhat surprising from "normal operation"--wherein the fan delay relay should keep the fan on for "several seconds" after the ign is turned off. This circuit/relay being defective does not, however, adversely affect other typical fan operation (low speed or high speed) pending engine coolant temp. This several second fan delay relay action is not what you're after anyhow.

As already mentioned, just grounding out (via your small-wired-switch) this coolant temp sensor will give you the direct connection you seek for fan operation (probably low-speed & = OK for your purposes).

Beware: You're going to forget it more than once & perhaps drain battery--Bo knows...

 

[GNVenom]

If the fan delay relay is good, the fan will run for 5 to 7 minutes after the car shuts off - if - the high speed trigger is made. That's the green/yellow stripe wire that triggers it.

The caspers fan switch allows you to manually trigger the relay thru the AC pressure switch connection.

 

[Renthorin]

When I shut the car off the temps are below 180 so not sure if it should run.

I just want something to move some air over the engine before I put the car into the garage otherwise it passes all that heat to the garage and I kennel my dogs there and they glare at me.

 

[GN Bob]

I have purchased a kit from Autospeed.com out of Australia to monitor engine load. They do a great job with instructions and workmanship from what I saw.

This is a description of their kit for an adjustable temperature switch:

"Economy Adjustable Temperature Switch

Ref: High Performance Electronic Projects for Cars - Silicon Chip Publications.
If you don’t need the display, or the huge operational range of the High Range Adjustable Temperature Switch with LCD, then this unit is a great alternative. It has an adjustable switching temperature up to 245°C, and it can be configured to trigger with rising or falling temperature. It has adjustable hysteresis (the difference between on/off temp) which is a great feature many other units do not possess. It can be used to operate cooling fans on a radiator or amplifier, over-temp warning lights or alarms, and much more. The small temperature sensor reacts quickly to temp changes. Kit supplied with PCB, NTC Thermistor, and all electronic components."


AutoSpeed - The World's Best High Performance Online Magazine

Part Number: KC5381

I haven't tried this one but it may be what you need to keep your dogs happy.


Bob

 

[Renthorin]

Splice a wire into the green wire on the intake located right below the tv/throttle linkage...its the one with a plug hooked onto a sensor that runs into the intake for the fans to kick on after a certain temp(well over 200 I think). Run this wire to your ashtray switch and the hook up a ground to the other side of the switch.

Hey, I unplugged the sensor (think I had the correct one). It goes straight down into the intake manifold, next to the fp reg. Had a single green wire that when unplugged had a small male pole inside.

I used some wire and ground that wire to a few random bolts in the engine compartment but nothing happened.

Does the car have to be in the 'run' position?
Does this mean I have a bad relay somewhere?

 

[garyk1970]

other than the delay relay,the high and low fan relays only work with the ign on. you need a new delay relay and trigger it with a switch before shutting off car.
the only option is add another relay and rewire.......

 

[Renthorin]

Well I tried it again with the key in the RUN position and it turned the fan on high so that's cool. I found this on GNTTYPE:

Run a wire from a ground location to one end of the switch and run another wire from the other end of the switch to the Green wire with a Yellow stripe going from the High Speed relay to the temperature switch connector (which is vertically mounted on the intake manifold just to the right of the thermostat inlet.) You can splice into the wire at any point. The fan will continue to run as long as the switch is in the On position, however, if you leave the switch On when you shut the car off, the fan will continue to run in the high speed mode for approximately ten minutes.


When I turned the key off the fan shut off, unlike what the above said would happen. Does that mean my delay relay is bad?

Not a big deal as I am more than capable of shutting the fan off by hand and I won't forget as the GN will be in the driveway while cooling down and I never leave it out there more than 15 minutes.

Thanks for all your help guys....it is just what I needed to know :smile:

 

[HellOnWheels]

May be wrong here but I "think" if a switch is installed between the sensor and ground that it has only to be temporily grounded and will run 7-10 minutes and shut off, w/o the ign switch being on??

HOW

 

[turbolou]

Reply

Tap into the green/yellow stripe wire at the larger of the three relays on the drivers fender.That is the fan delay relay. Grounding that wire should trigger that relay & engage fans.

 

[salvageV6]

Use one of these:

K2579 : Velleman UNIVERSAL START/STOP TIMER: Designnotes.com

Wire it as follows;

Momentary switch to trigger the add on Velleman timer, may need a ground signal or +12 signal for a trigger I didn't read the instructions.

Fused 3-5A Battery power source to one side of the Velleman relay on the circuit board, should be a terminal available for it.

Leave Hi-Lo fan switch in HI position and shut off car.

Wire output of Velleman timer board which will be a 3-5A +12 source now to the HI speed relay coil power wire, use a 3A diode in line with this new wire, banded end of a 3A signal diode, (radio shack under a buck) to the factory high speed coil power wire, brown wire on the relay. Don't cut anything just add it onto the factory wire with the diode in series with the new wire.

It will work as follows, your manual HI-Lo switch in HI position provides the ground trigger for the relay coil, activating the velleman board with your momentary switch causes power to be supplied through the Vellemans' own relay to the brown coil wire which will activate the factory relay up to 15 minutes, (time adjustable by a pot. on the velleman board.)

The factory wiring and fusible links will provide power to the fan when the factory HI speed relay kicks in which will now act like a delay relay, only one that will work and not kill your battery.

About $18 total in the kit and the switch and diode.

You could build one for less with Radio Shack parts but the kit is so cheap it isn't worth the 2 hours or so to design and build it.

The board layout and design is worth the savings for sure.

Good luck. :smile:

 

[Renthorin]

WOW...thanks for all that info. This morning I already wired the Hi-speed relay into my ashtray switch so I am all set.

I did tap into the green/yellow wire on the HUGE relay (delay) and it powered the fan but as soon as I shut off the car the fan shut off as well.

Does that mean the delay relay is bad? either way I like being able to power the fan whenever I want. I can leave the car in "run" but turned off when I get home for a few minutes and that is all I want.

 

[BlackMetal]

Good discussion right here, I thought I was the only one who didn't like letting my car soak in it's own heat after I put it in the garage. My car always runs 165-175 so rarely do the fans ever come on by themselves after I shut it off.

I'll have to track down this green and yellow wire and see what I can do.

I was already also considering the other "hotwire" trick where you splice the two wires together so the fan will run on HIGH even if it's only being signaled to run on Low speed.