Controlling fan with Terminator x Fan Control circuit

[toms68cst]

I'm helping a friend with a LS 6.0 installed in a 65ish C10. He's installing an electric cooling fan.

We're weighing the option of controlling it through a thermostat mounted in the radiator vs controlling it through the fan 1 circuit of the Terminator x. Of course, either way requires a relay.

A local radiator shop mentioned that the Terminator x fan control circuit does not work very well or is buggy and that a separate external thermostat is better.

Anyone ever hear of this? It sure would be a lot cleaner wiring wise controlling it from the ECU.

TIA. Tom

[HO455]

Since either method requires a relay and wiring to the fan I would try using the ECU to controller the fan first and if it turns problematic then add the external controller.

It may be the relay control voltage from the ECU is not 12v DC. A little research on the ECU will show if the fan control signal is 12v DC. If not then plan ahead to use a relay style that comes in both the ECU voltage and 12v DC. That way it will be just a matter a matter of swapping one relay for another and changing the relay control wiring from the ECU to the new external controller if the Teminator proves problematic.

[toms68cst]

Originally Posted by HO455

Since either method requires a relay and wiring to the fan I would try using the ECU to controller the fan first and if it turns problematic then add the external controller.

It may be the relay control voltage from the ECU is not 12v DC. A little research on the ECU will show if the fan control signal is 12v DC. If not then plan ahead to use a relay style that comes in both the ECU voltage and 12v DC. That way it will be just a matter a matter of swapping one relay for another and changing the relay control wiring from the ECU to the new external controller if the Teminator proves problematic.

Thanks. From what I could tell looking online, it's just a 12V signal off the ECU. We'll see today how it goes.

All the wiring was done by the previous owner and finding the Cooling output leads is proving to be a challenge.

[1972CheyenneSuper]

Take a look at this video, it should help with most of it.

https://www.holley.com/blog/post/how...minator_x_efi/

You'll be looking for this flying lead harness on the existing harness. This portion may be missing and you might just have an empty connector at the moment, but these are the terminals that are the inputs and outputs of the Term X.



Also, you may want to look up your exact model, but I believe most of these relay outputs are ground triggers, meaning you are switching your relay's ground connection versus providing it a switched 12V.

[LS short box]

On my LS swaps I've done it both ways. ECM and sensor in the radiator. The ECM is nice because you can adjust the on/off temp setting to your liking thru the ECM
Having said that my 98 Wrangler with a LS6/4L60E combo that I built 15 plus years ago I used a Painless fan control kit. Welded a bung into the radiator for the sensor. Has worked well.

[sfont66]

Originally Posted by toms68cst

I'm helping a friend with a LS 6.0 installed in a 65ish C10. He's installing an electric cooling fan.

We're weighing the option of controlling it through a thermostat mounted in the radiator vs controlling it through the fan 1 circuit of the Terminator x. Of course, either way requires a relay.

A local radiator shop mentioned that the Terminator x fan control circuit does not work very well or is buggy and that a separate external thermostat is better.

Anyone ever hear of this? It sure would be a lot cleaner wiring wise controlling it from the ECU.

TIA. Tom

I chose to have the Terminator x control the fans, so far no issues at all. It’s been 2 years and probably 3000 miles.
I haven’t heard of or experienced any problems like your radiator shop mentioned, I wonder if they have personally experienced issues or if it’s based on customer feedback?
It’s possible some of those issues were related to bad wiring or connections, grounds ?
I’m definitely not a wiring expert, but the terminator x seems to do a good job controlling the fans, i would recommend trying to use it if it doesn’t work out you can always go the other route.

[toms68cst]

Thanks everyone. My friend went ahead and wired the fan through the sperate thermostat. He said it worked ok except for some short-cycling. He could see the temp display on the terminator drop a lot when the fan kicked on. I suggested that he try the Terminator control as it allows you to select switch on and switch off temps.

I suspect the problems mentioned by the radiator shop have more to do with wiring issues or misunderstandings than inherent problems with the ECU itself.