View Full Version : Problem with cooling fan
Good Morning! Need some assistance with my electric rad fan not working all of a sudden. Has been working flawless for the last year I have owned the roadster. I thought I understood the I squared Million system, but now I am not so sure? A little setup: went to the store last Saturday and I noticed the temp gauge over 210. It always runs about 195, no matter how hot outside and how long sitting in traffic. I noticed the fan was not working (you can actually hear it at idle, as it is that loud!). Checked the fuse on the million box and looked good. so, let it cool down and start back up, I tried to use the override switch on the dash and no joy. I drive home and discover that if I am moving, it really stays at about 195 or a little cooler. Now, when I arrive at the house, the fan is running again!!!!???? So, now I figure it is probably a relay in the circuit? After I parked the vehicle and let it cool down, the fan will not work. Find the relay behind the dash and replace. Did not help. I have traced the wiring and really dont understand how it worked? I am an mech engineer and understand electric principles, but I am now stumped. I understand that the electronic million system works by completing the circuit to ground, but not sure how the dang fan actually works?
Gosh, this is getting long! Sorry! So, the wire coming off the main box is "CF7" and goes to the relay. If I move it to "CF6 - which is connected to my heater fan motor", everything works just as it should. Please see attached diagram....Any way to troubleshoot this any better? Sorry for the janky diagram, was drawing in my garage and all I had was pencil and paper.
Thanks for any advic191271191272e!!!
I'm not sure how the I Squared system works. When I tried navigating to their site it looks as though it may be hacked.
So, from your sketch, it appears CF7 should be providing +12 volts to relay terminal 30 (Common to NO&NC) and terminal 86 (one side of the relay coil). When either the manual switch or the thermostatic sensor closes, the circuit is completed for the relay coil, pulling in the relay and making the fan run.
A few things to check:
1.) Is CF7 providing +12 at the appropriate time? Sounds like it may not be.
2.) Does the fan motor actually work? Sounds like it might, since it works when connected to CF6.
3.) Do manual switch and thermo switch work properly? Sounds like they are.
4.) Is the ground at the fan solid - all connections in that circuit?
5.) You replaced the relay. Just remember, these days new don't necessarily mean good. A lot of components come out of the box bad. Might try a known good relay.
Do you have a volt meter? Check for power between CF7 and ground when the system is cranky and not working.
The fan is like any electric device. It needs power and ground to complete the circuit
Since a fan is a high current item, relays are used to provide power to the fan. Relays have a 12v power input that gets switched to a 12v output that goes to the fan. The switch in the relay is just like any other device and requires both power and ground to close the switch. If either power or ground are interrupted, the switch will open and cut power to the fan. The power that controls the switch can be turned on/off to control the relay, or the ground can be turned on/off to control the relay. Most fan circuits are ground contrloled and rely on a switch to complete the ground connection based on coolant temperature. This can be a thermostatic switch or an EFI control, or a manual toggle switch.
Things to check...
- good power and ground connection at the fan
- good relay
- switch controlling the relay is good
- all wire connections in the circuit good
First of all, Thank you for your replies. If you re-read the second paragraph, I change the terminal from cf7 to cf6, then it works like it is supposed to. Not sure if that is ok to leave there? Worried about 2 motors connected to 1 circuit and the potential for them to be on at the same time? So, that eliminates the fan and ground, relay and ground, switch and ground, thermostatic switch and ground. Which brings me back to the control box, I am wondering if that circuit is messed up? Don't really understand how to test? I suppose I could make a circuit with a light bulb to see if I can ground and it light up?Another thing I tried is moving to cf5 (fog light and relay) and it works on that circuit when I turn on the fog lights (that completes circuit to ground). Goofy right? I could certainly completely remove the fan circuit from the master controller and wire it up conventionally, like I did the electric power steering....But trying to figure out what happened? Maybe beyond my ability to troubleshoot.
Thanks again. Any other ideas? I believe there are those with these systems still out there that can weigh in. I-squared have sold their business I believe to Littlefuse and spun off a product called "infinity box". But have changed the look and have added a bunch of new features. Expensive too!!!! So, looking around in the forums for documentation has not been fruitful. The "other" forum has references to documentation, but the shared images are "404-not found"