Guys,

Just looking for a bit of advice. When I bought my car 11/2005, it had been crashed in the front. One of the problems I sorted out as it sat in my garage for 3 years was that the radiator fans weren't working. I found a burnt fan relay, replaced it and went ahead and put in the FC thermocouple.

The fans worked good after that but I wanted more control, so I added in my own set of relays in parallel with the stock relays. I have them wired so that when I activate my relays, they in turn activate the stock relays (3 of the stock relays anyway). When I activate my relays, the fans turn on high speed. That's the way it worked originally. When turned off, the cooling system works as designed by Mazda.

Since then the system started not working consistently, and I found a loose wire. It went back to working correctly. But recently, when I turn on the fans, only the driver's side fan will run on high. The other side will not work.

So, while I have things taken apart a bit to replace the intercooler hose that's split, I decided to figure out what's going on. While I had the switch on, the driver's side fan was running, I just reached down and spun the other side by hand, and it took off and started running on it's own. Turning the switch on/off both fans would come on as intended from that point on.

But I want them to both work consistently. It seems to me, that I have 1 of 2 possible problems. 1) That one fan is weak from wear / tear, needs to be replaced. Or, 2) my relay wiring is causing the problem. But I have my doubts on #2. Seems like a relay is a low power device that just closes a circuit and allows a higher power circuit to put power to something like fans, lights, etc. But for all I know (I'm no wiring expert) I could be wrong and my relays could be backfeeding and causing this problem.

With both fans working, it can pull the temps down from the mid 90's Celcius to like 86 Celcius in like 2 or 3 minutes (very nice). With only one fan, it takes MUCH longer, and sometimes cant do it at all if its very hot outside.

Any advice?


JyRO

 

Don't know these fan motors at all, but it sounds like they might have brushes, and one or more brushes could be worn down on one fan motor, making intermittent contact.

 

Sounds like you need to replace that motor. If you want to make sure you can switch the power wire between the motor, is the same result occur then you have a bad motor.