CCRM Question

[Andy Thompson]

Before I posted this I looked around as much as I could, as there has been multiple posts on the CCRM. Anyhow, this is what I'm experiencing. First things first, car is a 95 MTX, with the correct D sensor. Fuel pump works and car runs fine. My question and problem is, that the fan will only turn on with the A.C on... If I dont have the A.C on nothing.. I just bought it so I haven't tested anything, just noticed this issue. Is the CCRM working practical? 95 has the two speed fan, is one speed for when the A..C is turned on, and other for when it's not? Never had a cooling issue with my past Shos but that was over 10 years ago..

 

[sperold]

I think the higher speed fan is activated when the AC is engaged. But others will know more about that.

It could be the ccrm.

It could be the temperature sender, the one that talks to the PCM, not the one that runs the dash gage. The PCM cannot instruct the CCRM to turn on the fan if it is not told the engine is hot by the temperature sender.
I would start with that.

 

[Andy Thompson]

Was thinking about that as well... thanks very much!! As it does make sense!

 

[shorage]

Which one is the guage sensor?

 

[SHOMON]

The one for the gauge is the single wire sensor. It threads into the thermostat housing.

 

[BaySHO Performance]

The CCRM seems to be working fine as it turns the fan on under certain circumstances.

The ECT Sensor is in the housing below the rear head that's connected to the thermostat housing by a wide short hose. What I use: ECT Sender (Duralast) SU201 $26 Autozone

Pic shows a corner of the TB cover on the left with the ECT sender connector right below it. MTX PFE sensor housing to the right with a couple of Phillips screws.

 

[shorage]

The CCRM seems to be working fine as it turns the fan on under certain circumstances.

The ECT Sensor is in the housing below the rear head that's connected to the thermostat housing by a wide short hose. What I use: ECT Sender (Duralast) SU201 $26 Autozone

Pic shows a corner of the TB cover on the left with the ECT sender connector right below it. MTX PFE sensor housing to the right with a couple of Phillips screws.

View attachment 10223

Nice, i was gonna pick that exact ECT up because i got a code 21. Car wasn't warm, would that effect it?

 

[BaySHO Performance]

If it was an on demand 21, no. If it was a KOER 21, yes.

 

[shorage]

If it was an on demand 21, no. If it was a KOER 21, yes.

Yeah it was KOER. I will warm it up and check again.

 

[tracy_s_1993_atx]

I recommend against the Autozone ECT sensor. My SHO was waiting way too late for the cooling fans to engage. The sensor from AZ is not properly calibrated for the correct temperature for when the fans are supposed to start. The Autozone ECT prevented the cooling fan from staring until 224F.

Get an OEM Motorcraft ECT or the ECT sensor from Napa. I tested sensors from Autozone, Oriellyauto, Motorcraft and Napa. The closest to stock calibration was the Motorcraft and the Napa. The Autozone sensor was the furthest from the proper calibration.

 

[shorage]

I recommend against the Autozone ECT sensor. My SHO was waiting way too late for the cooling fans to engage. The sensor from AZ is not properly calibrated for the correct temperature for when the fans are supposed to start. The Autozone ECT prevented the cooling fan from staring until 224F.

Get an OEM Motorcraft ECT or the ECT sensor from Napa. I tested sensors from Autozone, Oriellyauto, Motorcraft and Napa. The closest to stock calibration was the Motorcraft and the Napa. The Autozone sensor was the furthest from the proper calibration.

This one? sooo pricey


https://www.napaonline.com/en/p/DEM...olant+Temp+Sensor&keywordInput=coolant+sensor

 

[zak]

Fan should switch to high on max AC setting, you should hear it speed up (during autocrosses would use this to cool the engine after a run, MAX AC and set the cabin temp to 80 or whatever ambient is). Can recall a corroded connector pin between the CCRM and the AC clutch circuit on my former 95 MTX that kept the fan from kicking on.

 

[NoSlo]

After operating temperature is reached, revving the engine at 2000 rpm a few minutes should get the low speed fan to kick on. If that doesn't work, coolant has to get up to 230F+ before the high speed is triggered (without AC), which is near the top of the temperature needle range.

Something noteworthy - the 1995 MTX SHO has a cooling fan unique to that year, with a connector right on the fan motor, instead of a pigtail coming off of it. It has two coil circuits, Brown/Orange wire for low speed fan, and DB (dark blue?) for high speed. It is possible for the CCRM relay for one of the circuits to be bad, for one of the pins or wires to be corroded or broken, or for the fan motor's low speed to have gone bad.

ATX instead uses a "dropping resistor" to supply lower voltage to the fans.

Here's a table of voltages measured at the ECT sensor, you can measure yours and see if it corresponds with expected or measured coolant temperature:
https://shoforum.com/index.php?threads/ect-diagnosis-and-high-temperatures.139695/#post-1514381"

 

[Greg Corcoran]

Had the same issue on my '95 MTX from the time I bought it until earlier this year. There were two issues: first for whatever reason the low speed fan had too low resistance across the winding and fried the contacts in the relay in the CCRM. After much wailing and gnashing of teeth found the correct '95 MTX only (apparently) replacement 2 speed fan motor and an new relay to repair the CCRM. That was only half the problem. The other was the ECT sensor was for some reason thinking the engine was about 60 deg cooler than it actually was. So the fan still didn't come unless the AC was on. Replaced with the correct NAPA sensor and all is well. One trick I learned form a Ford tech - to test your CCRM and fan motor disconnect the ECT with the engine running. the low speed fan will come on by default if they are OK.