My car did it when I first got it. That's what the fan recall is designed to do, run the fans if the thermoswitch has triggered for a certain amount of time.

You've probably done some of the tricks like turn on the parking lights and/or turn on the AC which kick the fans up on a stock ECU.

Regardless, the whole point of Mazda's fan recall is to run the fans for 10 minutes after shutdown if the car is running hot, 107deg. C hot, for a certain amount of time. It's a hack to get around the fact they had the car running too damn hot.

Dale

thanks for all the info!
I've searched a lot but still my problem has not been fixed..
my car's water temp, if i hold ie the 2nd or 3rd gear @6500k for 10-15 secs start to rise up to 95..
also, when there is load ie from 3000k, temps tend to rise again..and if i let the car role at neutral then they lower up to 88..
used to have great fun..but with this problem, i'm not able to enjoy my 7..
(checked the fans, changed the water thermostat and the water temp sensor so far..)
any ideas?
thanks!

Black7Conv,

How many years and miles are on your radiator? (See post #36.) Maybe you need a new one.

wstrohm i have a pwr radiator with 3000miles on it..

Radiator should be fine, then. What glycol/water mix are you using? For temperatures above -16°C (3°F) Mazda recommends 35% coolant, 65% water. (Information is from coolant mix table, page E-5 of RX-7 1994 workshop manual.)

Ethylene glycol transfers only about 57% of heat that water does. Too much glycol will cause engine to run hotter. Be sure to run distilled or de-ionized water to minimize electrolytic corrosion in the cooling system.

I do always run a 50/50 mix. Running straight water or a low coolant mix can lead to corrosion in the water passages. If you're doing a track event or something and need extra cooling, change the coolant beforehand then swap back.

Also, change your coolant once a year.

I've been through a LOT of motors, and you can tell the ones that have had coolant rusting away in the motor and ones that have been properly changed.

Dale

Evans NPG+ here...... lifetime coolant with zero water and zero corrosion :icon_tup:

thanks guys for the replies!
I'm using a 50/50 mix by BP. I dont know exactly what's inside but i'll have a look and let you know.
I just can't understand why the problem started out of the blue..is it due to the hot summer temps??
also, i've been thinking about NPG+..

Will a bad fan switch cause the 15 amp gauge cluster fuse to blow sometimes when the fans kick on?

no

Any ideas what will then? I'm chasing my tail on this issue.

Check your harnesses in the front wheel wells.

I found the issue. I traced my fan switch temp sensor wire back a little and found a spot where it was bare and almost severed. The reason that it was blowing the fuse only once in a while is because the coolant temps weren't always getting high enough to trip that sensor. I think mine may already have an FC fan switch, because the fuse seemed to blow right about 97*C. My fans turn on low at 90*C, probably through the PFC tune from Rotary Performance. Time to rewire some stuff, which I planned to do anyway, but now it's priority.

So any year FC thermo switch will work? Is this a dealer only part?

The Mazda P/N for the FC thermoswitch is PN41-18-840. Don't know if this is available from auto parts stores. Bought mine from Ray at Malloy.

Is there a way to get the plug ends from the harness or a replacement pigtail for the fan sensor and ECU sensor? My ECU temp plug broke and the fan plug isn't too far from it.

I asked Ray Crowe the same thing and he said no, not without a new harness. Somebody mentioned you could get the smallest female terminals from Radio Shack and see if they fit snug over the male connection at the plug. At that point I would make a "pigtail" lead and put a weatherproof connection on the wire harness, solder the radio shack connection and fill the connection at the sensor with epoxy. The Pettit fan switch requires you to put a new connection on the wire harness because their switch comes with a lead already installed into the sensor. I just decided to stick with the pettit switch and go with their 180 thermostat

Thanks very much. I just ordered the Pettit fan switch, so that will solve one of my issues. All of my engine bay wires are so old and crusty that the Rywire replacement harness is starting to look like a good route.

I just installed the Pettit fan switch and 180* thermostat. In the process, the ECU coolant sensor plug fell the rest of the way apart, the spade side of the OEM water temp gauge wire broke, and the fan switch wire broke really far back when I was trying to strip the wire to hook up the Pettit switch. Gotta love how brittle 20 year old turbo car wiring can get.

I wired everything back up temporarily to see where my fans turned on, and it was about 180*F according to the PFC (82*C), so I'm happy with that. One step up and two steps back I guess, but I'll be placing my order for that new harness soon.

I'm going to go ahead and put a new green ECU sensor in when I replace the wiring, so which one is it in the catalog? They list a primary and secondary sensor, but have no diagram to reference. I'd assume that it's the primary sensor.

Dale - Have a 1993 with a PowerFC. I want to adjust cut-in temperature of the fan speed change as you describe. Trouble is if I look in the FC-Commander Manual the only reference to monitoring/changing the cut-in temperature, (refered to as "Wtr Temp") appears to have a totally different function and seems to be a Water Temperature correction table for various engine temperatures. I must be missing something and would appreciate your (or anyone else's) input. The Power-FC Model # is PFC FD3S4 020-5156. I'm using a an FC Commander Instruction Manual that I pulled off the Internet (cos. the original one was in Japanese!). This downloaded one has a product Code 415-Z001 - is this the correct manual? Note: I've not actually tried changing the Commander setting yet - this question is just about the instructions which seems to be a reasonable thing to read before doing any changes. Thanks. Dave

Agreed.

Remedy: Electric Water Pump and fans on, after engine is off. shouldn't take more than a few minutes to get that engine cooled off. heck, I bet 90 seconds would be enough.

Ground connections to fan motors
 

On my 1993, depending on operational mode, 2 of the 4 fan inputs can be connected to ground . One of them only connects when relay # 3 is closed. The other is permanently grounded via a solid connection to the body, (per the electrical manual). I think the fan ground body connection in my car has broken. Can anybody tell me where this connection is located on the body.

Thanks

Dave

Ground Point [circle] 2
 

Page Z-40 wiring diagram in the 1994 FSM shows the fan motor grounds at point [circle] 2. Page Z-41 shows that point located in front of the right (looking forward) fan motor. It's not clear exactly what it ties to.

Ground Point
 

Wstrohm -

Thanks for your input.

Looked all around that area but cannot see a ground point. I'm sure it's in there somewhere but without starting to take things off at the front I can't see anything. So I've just gone ahead and wired into the relevant (black) wire on the male connector to the one of the fans, (which goes to the yellow ground input on the fan). It's interesting that this grounds BOTH fans, so the two ground connections were already joined together somewhere in the cable harness but were not connected to ground! Ah, well, I'll probably never know exactly what happened in there, but meanwhile it's now working like a champ.
Anyway, as a result of this episode and having checked out all the connections to the fan and the fan relays, I now have a very good understanding and diagrams of the whole system, along with all the various wire colors (and changes of the colors as they move through the various connectors), and will be happy to help anyone with similar problems.

Dave

I dont know where to find it on the powerFC commander. it may not be available on the commander. I do know, however, that on the Datalogit, you can find the setting under the "Settings 3" tab. "Fan vs Water Temp" function.