95 Gt...couple electrical questions

[THE COBRAMAN]

Short back story...

Bought this from a guy who bought it to flip and got in over his head. They swapped in a used CCRM to fix the no-start issue, then got overwhelmed.

After replacing the harmonic damper, runs pretty good, but no cooling fan. Used the article at 94-95 Mustangs Electrical CCRM - Mustang-Tech to do some diagnosis. Found that when grounding the wire to terminal 17 of the CCRM, the fan would run, and all other in/outs referenced in the article tested OK per the article.

Am I correct in thinking that after I check for continuity between the PCM and the CCRM on this wire, I should be looking for signal problems from the temp sender?

Also, there has been some "creative" wiring rework done, which seems OK, with this exception. There is a large red/orange wire that has been clipped off near the ABS module. I believe it is the wire in the blue box on the attached (borrowed) picture...and I have no clue as to where it is SUPPOSED to terminate.

Aside from an ABS lamp (module cover missing and components appear weathered/damaged), everything else seems OK..just need a rear seat

Any input is GREATLY appreciated

 

[Adam95GT]

View attachment 226811


it may go to secondary air injection tracing it by eye... your car have smog/egr?

 

[HISSIN50]

Did Pin 17 achieve ground when the AC is turned on (or the car reached 230*F [if you felt like running it that hot])?

You idea to test continuity is fine.

There are other work-arounds if you wanna fix it on the cheap (if low speed functions properly). You might find the driver is not functioning properly for high speed. Such solutions include switching the low speed output over to the high speed fan terminal, and then using a relay to energize the fan when the AC is turned on. You could also go to an aftermarket fan controller or fan switch.

Good luck.

 

[THE COBRAMAN]

Did Pin 17 achieve ground when the AC is turned on (or the car reached 230*F [if you felt like running it that hot])?

Good luck.

No, when A/C was turned on, no grounding of the wire occured until I probed it with a test lamp (which then energized the fan). I have yet to attempt unplugging the ECT to see if it fail-safes, but the low fan also does not come on. In fact, grounding 17 first ran low fan, then when A/C was on, high.

Did a bunch of reading here on this LATE last night, including a lot posted by yourself, so I will reattempt testing now that i have more info

I would prefer to use the OE setup, but I understand that it'd probably be a lot easier on what little hair I have left to go to the aftermarket for a fan controller...but I would like to see if the OE setup will work. Guess I'm one of those "why is it" guys.

Thanks for the help

 

[THE COBRAMAN]

View attachment 226729


it may go to secondary air injection tracing it by eye... your car have smog/egr?

Yes, EGR, and appears to have the original emissions equip intact

Looks like about where C109 is, but I don't have a real clear idea at this point. Need to find another 94/95 to see what it looks like.

 

[THE COBRAMAN]

Tested some more...with key off, applying 12v to terminal 17 runs fan
With key and A/C on, grounding 17 runs fan
17 shows no continuity to ground
Also am not seeing any power to terms 6 or 7 when hi fan should be on

Do not see any power to the 10 amp monitor fuse in the underhood box....is this fuse found anywhere in the circuit in the shop manual?

Unplugging the ect sensor will make the fan run with a check engine lamp on.

Really lost now...but at least I know the fan is good!

 

[HISSIN50]

It's late and I'm wiped so apologies if I missed something.

I never ran 12V to Pin 17 so I'm not sure what to make of that.

When you ground Pin 17, you obviously get 12V on pins six and seven, right? Otherwise, without 17 being grounded, six and seven will be cold.

The 10-amp-EDF-monitor fuse doesn't show voltage normally that I recall. It never did when I tested it anyhow. I never found much for info anywhere (including the shop manual) on the EDF monitor. Because it's solid state, it was just a variable to me. If anyone finds something, please let me know so I can ammend the Wiki tech note.

When you unplug the ECT and it runs (should be low speed), that suggests the EDF monitor functions and the illuminated CEL is normal.

I understand you wanting to get the OEM set-up to function. I think some of the issues people have are with the driver(s) for the fan. Yours sounds like more than that since your issue is not just temperature-switching related (normally it's one speed or another not engaging at the proper temp threshold).
For jollies, you might wanna check the ECT calibration. You'd need an aftermarket temp gauge or the ability to view PIDs to really nail it (or some means of accurately determining coolant temps in the intake).

If you do get fed up, a 25 dollar temp switch (better than an adjustable controller IMHO) should get you a fairly reliable set-up if the CCRM relays are in decent shape. Other options are more expensive.

 

[Adam95GT]

two of the connectors in that harness go to the fan some how... i touched them together and blew the fuse for that today. Also the red wire goes in on a side with 4 pins if we are indeed talking about the same connector. only 3 pins come out the other side on my car that red is hooked in to nothing on the male side of the connector

Maybe useful info

 

[THE COBRAMAN]

UPDATE....

After running the testing again, I finally considered that perhaps the solid state compoents were bad. I gambled $15 on a used CCRM from our local Pull a part (knowing that the PO had installed a used one). Seemed to fix it, so we'll see how it goes.

Thanks to HISSIN50 for the guidance and Adam95GT on the other question!

 

[HISSIN50]

Nicely done!