Confusion about high/low coolant fan.

[Roc87]

Wiring up the Camaro (Soon) with the t-type drivetrain and I'm confused about the high/low fan. I won't be running a/c. And I doubt I will run the Delay relay. Now let me see If I have it straight, the ecm controls the low speed (chip change can control the low speed turn on point too right?) and the coolant fan temp switch (in the manifold under tb) controls the high speed fan.

Now, I'm not too sure that I'll be using the T-types fan motor and will probably be using the Camaros electric fan (Only two connectors) Any ideas on how to wire this? I would really prefer to have the fan come on like it should rather than use a toggle switch because my wife might drive the car sometime.

BTW, why was there a high/low speed? Seems like a single speed would have been fine.

TIA

 

[Steve Wood]

OEM had the high speed come on when the ac line pressure reached a certain point, or when the fan temp switch saw a certain level of temp.

The fan had a resistor block on it that dropped the voltage reaching the fan and this was low speed. High speed, the 12+ went straight to the fan instead of thru the resistor.

Many of us have eliminated the resistor block so the fan runs on high all the time.

I guess the factory may have been trying to keep the noise down down with a low speed option? On the other hand, everytime the ac came on, the high speed came on so down here in the south, the only time it was on low was in the winter when we had a cool day.

If you need more detail, let me know.

 

[Roc87]

So I don't have to have that resistor? I'd rather just have the fan going as fast as it can when it's needed anyways. I don't even need to put in a diode to keep from backfeeding the relays, right? Thanks for the help!

 

[Steve Wood]

no need for the resistor...just go straight to the fan(s)