Does anybody know what the turn on temp is that the fan switch is set for on the auxiliary fan?
86-89 would be the years for the aux fan that I'm interested in.

 

I wanna say 215 was original on my 86, but it could've been 225

 

238F
Main fan factory programmed to run @ 228F

 

well, that's too high. I will just tie it to the brake pedal switch.
When I come to a stop, the fan will be actuated by the stoplight power to a relay, and when I take off, it will stop, and the wind will take over.
Don't know why I didn't think of it earlier. If I need it on longer, I can install a switch for stop and go traffic.

 

Aux fan has its own relay on radiator shroud beside drv side headlight.
( relay goes to ground at temp switch in head so would need rewiring for feed from brake switch )

If you consider your operating temps are too high ,you could always splice in a temp switch to make the main fan run at lower temp and not need the aux fan to run?

http://www.racerpartswholesale.com/p...n_Accessories2

 

main fan is run by the ECM with inputs from you vehicle speed sensor and the sensor reading from the front of the intake. The aux fan is run by the sensor in the drivers side head. You can swap in one of these:

http://www.parts123.com/parts123/yb....Z5Z5Z50000050F

Corvette central has 4 different degree settings to choose from. If i had and Aux fan i would use one of these but my car has no A/C or anything up front

 

Correct.........again.

 

Pretty innovative trigger!

 

I have had my 86 for around 16 years. My indicator tells me the computer turns the fan on at an indicated 232 degrees, and turns off at 215 degrees....with the air on, it turns on at 220 degrees and turns off at 205 degrees.
This switch is for my 1957 Chevy pickup. I have worked it out. the main fan will have 3 triggers:
1. temp sensor............grounds the fan relay coil
2. manual fan switch....grounds the fan relay coil
3. brake switch...........powers a relay that grounds the fan relay coil through an arm relay from the key on the positive coil contact
I think the temp sensor is too high, but I can't find the switch I bought for it when I started the project.
I bought a temp switch for an 86 Buick Grand national, and it came on at 200 and went off at 185.
I will have to root around in my storage shed, or open the hood on my 86 and see if it resides there.
Anyway, on the 86 corvette, I tied the coil of the aux fan relay to the power wire on the main fan, and now when the big fan comes on, the little one does too.
I went from running at 224 average to 202 average in the summer with a 2 row alum. radiator.
Right now, Dec. 1, with a 160 thermostat, it runs right around 170 on the freeway, and 185 in stop and go.
I love this car. Right now, my $300 383 needs a tune, but it is ok. I just wish I'd used a stock converter. The higher stall speed sucks in traffic.

 

I have a adjustable thermostat on my 85 that I purchased from JC Whitney. It has a bulb that sits in the radiator hose. It powers the main fan and comes on about 205 or so, and I am not sure where it shuts off. My aux fan never comes on.

 

I like the brake pedal idea. Just make sure that you parallel your circuit with the existing circuit so that either the brake light or the temperature will activate the fan relay.

 

The late CFI-EFI thought me the importance of accuracy;
by kicking my a*se every time I posted anything other than 100% factual and unable to be interpreted in a way other than I had originally intended

 

I did it, manual switch, temp sender, and brake pedal.
I got the brake pedal input from the turn signal switch white wire. saves me from going outside the cab on the 57.
works like a charm. I used a relay on the brake pedal circuit, and even with the car off, the brake pedal energizes the relay. relay is fused, and the brake light circuit is fused. The deal was I had to use 2 sources of 12 volts.
Ignition power and brake lights power. Ignition turns off, and the brake circuit is hot all the time.
Since the key activates the fuel pump relay off of an "arm" relay, with the key off, the relay clicks but the fan doesn't come on.

 

I love the idea of tying it into the brake switch. Good thinking.