Good morning,
If you're like me, you're going to slap your forehead when you figure it out. The 2 connections at each fan are for power and ground. Here's the kicker--you don't ground the resistor. It's only a pass-through of the power wire. The low speed wire goes to one end of it, (one terminal) and the other end (other terminal) is tapped into the power wire (high speed) that goes to the fans. The CCRM does the magic of determining which of the two power wires, low or high speed, is energized at one time.

One other tip, in case you need it. When I hooked mine up, the respective wiring diagrams for the Miata vs Mustang showed that the dash button on one completed the ground circuit to power the compressor, and on the other one it completed the power circuit. The solution was to wire a cheap relay to reverse the polarity of the dash button.

 

Awwww! I had that thought about the resistor but wasn't sure. That makes much more sense. I don't plan on AC, but sounds like I'll have to wire the relay anyway. Any more advice on what wires need the relay? I'll dig up wiring diagrams but wiring diagrams sometimes just confuse me more than they help me sounds like that's the last piece of the puzzle though!

 

Went ahead and spliced the high and low wires together, and ran them into the high only, bypassing the resistor. So far, I'm not sure I've had the motor on long enough to have the fans turn on. Currently its open headers, and I'm trying my best to minimize the amount of times I **** of my neighbors. However I did get it on long enough to get the coolant temp to read just about half way.. and the fans didn't kick on. I wonder if its that relay you said needs to be spliced in? So not 100% sure what I'm looking for and how to reverse polarity... Is it the wires going to the AC button (even though the AC isn't being used)? Thanks for any help!

 

Reversing the polarity is only for the A/C circuit. If you are using the Ford coolant temperature sensor on the passenger side of the front of the intake manifold (that's where it is on the SN95 engine), then if I recall correctly the ECU should be reading it and sending the appropriate signal to the CCRM to turn the fans on low speed at the appropriate time.

 

Perfect! I'm going to rewire so I'm utilizing the low speed resistor here shortly. Funny enough- I didn't have the plug for that one, so I did a quick wire up to see if they'd come on merging the high/low. But I have since gotten the connector, so I'll rewire and see how it does. Good to know I shouldn't need another relay somewhere. Thanks!

 

Looking back over my notes from several years ago, here's an old thread I copied from one of the Mustang sites. It tells you how to wire up an override for the CCRM, to turn on your fan whenever you want without waiting for the CCRM to do it. I used it on mine in hot weather, before I switched to the Contour fans. It's pretty easy.

95/GT/5.0 01-20-2003 10:53 PM
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Elect.cooling fan over-ride
1 Attachment(s)
Manual Fan Control Switch Installation
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The fan is controlled by the PCM and/or the Constant Control Relay Module (CCRM), when the EEC detects certain temperatures it will switch the fan to either it's low or high speed settings. The A/C will turn the fan to high speed when it is set to max.
But how can you bypass both the EEC and CCRM and install a manual switch to control the fan operation?

First you will have to disconnect the NEGATIVE battery terminal and locate the CCRM and a pin on its connector.

The CCRM module is located LEFT (you looking at engine) of the radiator reservoir/overfill bottle.

Now that you located the CCRM, remove the connector, you will need a 6mm socket to detach the connector from the CCRM housing.

5.0 models:
Locate PIN / WIRE #17 (GREEN with PURPLE stripe) on the connector, it should be easy to spot, the connector has numbers for each pin.

Next you will have to TAP a wire to #17, don't CUT THE #17 WIRE !!!, you could use a scotchlock connector to tap into it, OR REMOVE about 2 mm of insulation and wrap your wire to #17.

Get a second wire and connect it to a GOOD GROUND, now run BOTH wires into the cockpit through the firewall, choose a spot to install the SWITCH, connect the wires to each of the 2 switch terminals.

Now is test time, turn key to ON, and flip the switch......READY!!!

 

That's great! I'll probably do that as extra insurance.

 

i am installing a s95 conversion,right now on my miata,i am having problems with the oil sending unit hitting the bracket,where the a/c is mounted,how did you get yours to clear,cant find a shorter oil sending extension.

 

I ran mine with no AC so I just removed the bracket.

 

I used small pipe fittings - an elbow to angle away from the A/C bracket so I could install the Miata oil pressure sender.

 

On mine, I first used the large "real" Miata sensor and brass fittings and about a two inch pipe from the hardware store to angle it away from the compressor. But then I wasn't happy with the weight of that sensor supported only by those fittings and a 3-4" reach. I then tried a couple of different Ford extenders made for this purpose on various Ford vehicles, but none of them worked well enough with the size of the Miata sender.

This really sounds redneck but I found that the flexible section of the old clutch line, much like a rubber brake line, fit the sender perfectly. So, I used it to make a remote-mounted sensor. Made a little bracket, bolted it to the sway bar tower mount, clipped the sender on it, fabbed a fail-safe ground, and it worked fine.

TM