Getting pretty tired of my fan not turning on...

[5.0Torx]

Hello,

I've got a very bone stock '94 GT 5 speed with 71k miles on it. I've got an issue with the cooling system. The fan rarely seems to turn on by itself. Most of the time, I jump the gun once I see the temp gauge going past halfway and turn the AC on. This always turns the fan on, and then the temp gauge crawls back to the N in NORMAL. I realize the stock temp gauge is not worth a damn but I will say that, for the most part, it is consistent.

Today, I turned my engine off after driving through 45 minutes of stop and go traffic, and was delighted to hear water boiling. Sure enough, I popped the hood just in time to witness the coolant boil over the top of the overflow tank and begin the process of pissing its guts out all over the driveway.

I am tired if having to run with the damn AC on all the time. I would consider a manual fan control. I have an autometer temp gauge waiting to be installed. In conjunction with a coolant flush, new radiator, and a good bleed, do you guys think this would be a viable long term solution?

 

[toyman]

Since the fan comes on when the A/C is turned on that means that the high side fan is working. The problem could be a couple of things. If you check on how to pull codes the first part of the diagnostic routine cycles the fan from low and then high. The fan motor connector are known to fail due to heat. If the fan doesn't come on low check the wiring closely to see if the low side lead is connected. The other possibility is the fan relay in the CCRM. If that is the fault you need to replace the CCRM. This site should help you trace the wiring.

 

[screamin5oh]

its a commom problem with these calm down thow easy 1 wire fix,. jump the ccrm fan relay wire to a ground, it will keep your high speed fan on all time thats what i do, i believe its the green black wire it, i can look and tell you what one it is, you dont have to cut any wires just tap into it and ground it out. if you google for it there is write ups on it also all over

 

[HISSIN50]

scream is talking about ccrm pin 17

a quality aftermarket controller is a viable option

 

[chaos254]

I feel ya, I just realized my fan wasn't turning on either. I fired mine up today after its been sitting for awhile and saw the gauge creep up to the M. I know they are not accurate but it is all I have to go by until I get my clock pod. I just saw this thread so I went and checked to see if it would kick on with the A/C and it does. Are there any negative effects of jumping the ccrm fan relay like you guys suggested?

 

[HISSIN50]

Mike, since the thing is already not functioning properly, probably not a whole lot of harm to be done.

I can dig up a diagnostic note (it's the one that used to be on the Wiki) if you or Torx want to try and troubleshoot the system.......

 

[95Vert383AOD]

I just bought a CCRM off EBAY for around $35 The CCRM's listed for the "94/95" Mustang are more expensive. So i searched CCRM and arranged from cheapest to most expensive and matched the part number. At that price why would i bother hacking up wires? lol

 

[HISSIN50]

Not all issues are from the CCRM.....................

 

[chaos254]

Not all issues are from the CCRM.....................

exactly, if you can find the diagnostic info, that would be great. So it could be the wiring, CCRM, or the fan itself, anything else I'm missing? I'd rather not throw money at it so I'll ground the 17 pin temporarily but I would like to figure out the real issue. Thanks hissin

 

[HISSIN50]

Fan relay diagnostics (EDF and HEDF):
Low speed fan relay diagnostics (the fan circuit is rather broad given the EDF module), so only relay ins/outs are noted here):

If low speed isn’t coming on, but you are getting 12 volts to CCRM Pin 14 at or greater than 208*F and the fuses are intact,
Check CCRM Pins 1 and 2 for 12 volts when the fan should be on. If there’s not 12 volts:
Check Pin 15 for ground.
Check pins 3 and 4 for constant 12 volts.

If high speed doesn’t come on at ~228F or with the A/C turned on, but CCRM Pin 17 shows continuity to ground:
Check CCRM pins 6 and 7 for 12 volts when the high speed fan should be on.
Check Pins 3 and 4 for constant 12 volts.
Check Pin 13 for key-on 12 volts.

 

[chaos254]

Fan relay diagnostics (EDF and HEDF):
Low speed fan relay diagnostics (the fan circuit is rather broad given the EDF module), so only relay ins/outs are noted here):

If low speed isn’t coming on, but you are getting 12 volts to CCRM Pin 14 at or greater than 208*F and the fuses are intact,
Check CCRM Pins 1 and 2 for 12 volts when the fan should be on. If there’s not 12 volts:
Check Pin 15 for ground.
Check pins 3 and 4 for constant 12 volts.

If high speed doesn’t come on at ~228F or with the A/C turned on, but CCRM Pin 17 shows continuity to ground:
Check CCRM pins 6 and 7 for 12 volts when the high speed fan should be on.
Check Pins 3 and 4 for constant 12 volts.
Check Pin 13 for key-on 12 volts.

Thanks hissin.. I have not gotten a chance to diagnosis this yet but I will post up what I find.

Sent from my ADR6425LVW using Tapatalk 2 Beta-6

 

[muhstang1]

I had a "fan not working" condition in the past but has since been resolved.
In addition to this problem, I also had a "fuel pump not working".
I had fuel pump hooked to toggle switch for a year and the fan hooked up to the fog light switch............After investigating multiple mustang sites, looking for a fuel pump fix, I went with the stator (PIP) replacement...Actually, replaced the distributor......fuel pump fixed, and to my surprise, the fan now worked.....I can't explain why...maybe somebody else can...That's my story....good luck!

 

[toyman]

Thanks hissin.. I have not gotten a chance to diagnosis this yet but I will post up what I find.

Sent from my ADR6425LVW using Tapatalk 2 Beta-6

Let me try.

Fan not working may be your expectation and not related to the ECU temp trigger. The low fan will come on at 208* or 220* depending on the reference source. The Ford CD service manual states 220*. If your gauge is like mine that wouldn't occur until you see the needle between the R & M.

Fuel pump not working may have been an incorrect diagnostic unless verified by a pressure testing the fuel system under operating conditions. If it was a guess at being a fuel problem it may have been incorrect with the problem being the PIP all along.

Now this is a wild guess, but by forcing the fan on may well affect how the ECU interprets various sensor inputs one of which may have been the ECT.

That's my story.

 

[95Vert383AOD]

200+ is a tad warm for my personal taste. Not much room for error there on say a hot day or cooling system failure. Especially if you are running aftermarket aluminum heads.

I programmed my SCT for 180 and have a 180 thermostat. My temp reads a steady 180 with maybe a +5-10 deg. on really hot days in standing traffic.