Cooling fans don't come on

Help, I have a 69 Series 2 with cool cat radiator and fans and a classic air a/c unit
when I turn the a/c on the cooling fans come on, but under normal operating the
when the temperature gets to above normal the cooling fans do not come on.

Did you check the otter switch?

Yep, what Bart says. You know the fans work, its either the otter sw or the relay. You can simply disconnect the wires from the otter sw. and connect them together with a jumper of some kind. Turn on the ign. sw. the fans should come on. If they don’t then start looking at the relay.

thanks for the suggestions
will try

I bypassed the otter switch entirely, could not trust it. I have a manual switch on my dash that controls the fans. When in traffic I turn on the fans because I know the temp is going to rise fast and I want to be ahead of it. When on the highway, no fans.

how’s this done? through the relay or directly to the fans?


First off, check the FUSE. You can test the fan switch by simply shorting the two contacts together. If the switch is bad, contact me offline.

Use the manual switch through the relay. That way you are not routing full amp draw through your switch.
You can also have the Otter switch AND a manual switch. Leave it as an automatic function and when you want to you can turn them on manually. Both can use the same relay.

Thanks to all with the great suggestions on curing my fan problem.
As it turned out when the last owner had the radiator replaced and classic air
added the mechanic replaced the stock wiring with an aftermarket controller, Flex a lite,
going through a series of tests and talking to the company determined that the unit had
failed and a replacement was obtained. now the fans work with the ac and temperature sensor.